https://wiki.batc.org.uk/api.php?action=feedcontributions&feedformat=atom&user=G8YTZBATC Wiki - User contributions [en-gb]2026-08-03T17:40:42ZUser contributionsMediaWiki 1.35.6https://wiki.batc.org.uk/index.php?title=Lynx_RPi5_Dual_RX&diff=12648Lynx RPi5 Dual RX2026-07-27T15:17:32Z<p>G8YTZ: </p>
<hr />
<div>== Lynx and Knobler ==<br />
<br />
'''Lynx''' is a full DATV receiver for the Raspberry Pi 5 — not a control panel bolted onto someone else's decoder, but the whole receive chain: tuning, decoding, a genuine live picture on screen, and, when you want it, real diversity reception — two independent tuner inputs combined automatically, so a fade on one path doesn't have to mean losing the shot. Pair it with '''Knobler''', its companion rotary-dial remote built on the M5Stack M5Dial, and you've got a receiver you can actually run from across the room — glance at it, spin the dial, get on with your day.<br />
<br />
It's actively developed, and it already does three genuinely different jobs well: a QO-100 ground station, a repeater input receiver, or a straightforward home DATV set-top box — same software, same interface, whichever one you're actually building.<br />
<br />
'''Requires a Raspberry Pi 5 (4GB or better).''' It won't run on a Pi 4 — the decode workload genuinely needs the newer hardware.<br />
<br />
This page gives a brief overview of both. See [[#Getting_Started|Getting Started]] below for setup instructions.<br />
<br />
=== Get Started ===<br />
<br />
Ready to get something on screen? Here's everything you need.<br />
<br />
* '''Lynx''' — [https://github.com/G8YTZ/lynx-datv-receiver source code, install guide, and full documentation]<br />
* '''Knobler''' — [https://github.com/G8YTZ/lynx-knobler source code]<br />
* New to Lynx? The [https://github.com/G8YTZ/lynx-datv-receiver/raw/main/docs/lynx_install_guide.docx Installation Guide] takes you from a blank SD card to a working receiver in one sitting, including a one-line installer.<br />
<br />
=== Lynx ===<br />
<br />
Built around the Picotuner, Lynx gives you a full receiver, not just a viewer:<br />
<br />
* A local web UI (default port 8080) for status, tuning, and configuration<br />
* Live decode status — lock state, MER, and related quality metrics, read from the Picotuner's status broadcast<br />
* A preset system for quickly recalling known frequencies/symbol rates across plugs (including saved presets created from the web UI)<br />
* Optional receive diversity combining across two tuner inputs, with automatic MER-based switching and a "hard freeze breaker" safeguard against repeated lock loss<br />
* Optional notifications — Slack, QRZ logbook lookups, and GPIO-triggered outputs (e.g. driving an external "on air" indicator) — each independently configurable and disabled by default<br />
* Optional RTMP relay of the decoded stream<br />
<br />
Configuration lives in a single YAML file covering site details (callsign, locator, location), the Picotuner connection, presets, streams, diversity settings, and notification integrations.<br />
<br />
Full documentation, including an install guide, a Web UI reference, and a guide to the on-screen display, is kept alongside the source: [https://github.com/G8YTZ/lynx-datv-receiver/tree/main/docs docs folder on GitHub].<br />
<br />
=== Knobler ===<br />
<br />
Knobler is a physical companion display for Lynx, built on an [https://docs.m5stack.com/en/core/M5Dial M5Stack M5Dial] — a small ESP32-based device with a round touchscreen and a rotary encoder. It polls Lynx's web API directly and gives you a dedicated, always-on physical readout and control surface, separate from the web UI.<br />
<br />
'''Current capabilities:'''<br />
<br />
* Live status display (lock state, signal quality) with a configurable poll interval<br />
* A menu system for browsing and selecting presets and streams via the rotary encoder, with an auto-timeout back to the normal display<br />
* Self-service Wi-Fi setup — no need to hardcode network credentials into the firmware or edit code to get it on your network (see below)<br />
* Automatic discovery of the Lynx receiver on the local network — no need to hardcode or manually enter an IP address<br />
<br />
==== Wi-Fi Setup ====<br />
<br />
On first boot (or if it can't find a previously-saved network), Knobler opens a temporary Wi-Fi access point of its own and displays a short prompt on screen. Connecting a phone or laptop to that access point brings up a normal Wi-Fi configuration page, where you select your network from a list and type in the password on a proper keyboard — rather than fumbling through SSID entry on a 1.28" touchscreen.<br />
<br />
Once configured, credentials are saved on the device. If the saved network ever becomes unreachable (moved out of range, router replaced, etc.), Knobler automatically falls back into setup mode after a short timeout, without any need to reflash or reconfigure it by hand.<br />
<br />
==== Auto-Discovery ====<br />
<br />
Rather than requiring a fixed, manually-entered IP address for the Lynx receiver, Knobler broadcasts a small discovery request on the local network on startup. Any Lynx instance running current software answers directly, providing its name, callsign, IP address, and API port — so Knobler finds the right receiver automatically, even if its address changes (e.g. after a router reboot hands out a new DHCP lease).<br />
<br />
=== Getting Started ===<br />
<br />
'''Requirements:'''<br />
<br />
* An M5Stack M5Dial device and USB-C cable<br />
* Arduino IDE, with ESP32/M5Stack board support and the required libraries (M5Dial, WiFiManager, ArduinoJson) installed<br />
* A Lynx receiver running current software (the discovery responder must be present — see below)<br />
* A computer or phone to complete Wi-Fi setup<br />
<br />
'''Lynx:''' the [https://github.com/G8YTZ/lynx-datv-receiver/raw/main/docs/lynx_install_guide.docx Installation Guide] covers everything from a blank SD card to a working receiver, including a one-line installer script.<br />
<br />
'''Before flashing Knobler:''' make sure the Lynx receiver is running a version of the software that includes the discovery responder (it prints a line similar to <code>Discovery responder listening on UDP :9998.</code> on startup). Older Lynx installs will need updating first, or Knobler won't be able to find them automatically.<br />
<br />
A full step-by-step Knobler installation guide — covering Arduino IDE setup, board/library installation, flashing, and first-time Wi-Fi configuration — is not yet published separately; for now, see the [https://github.com/G8YTZ/lynx-knobler Knobler repository] directly.<br />
<br />
=== Status ===<br />
<br />
Both projects are under active development. Known limitations at time of writing:<br />
<br />
* If more than one Lynx receiver answers a discovery request on the same network, Knobler currently connects to whichever reply arrives first — a picker screen for choosing between multiple receivers is planned but not yet built.<br />
* There is currently no on-device way to force Knobler back into Wi-Fi setup mode (e.g. to deliberately switch networks) short of clearing its saved credentials via a computer.<br />
<br />
=== See Also ===<br />
<br />
* [https://github.com/G8YTZ/lynx-datv-receiver Lynx source code and documentation on GitHub]<br />
* [https://github.com/G8YTZ/lynx-knobler Knobler source code on GitHub]<br />
* [[Picotuner]]<br />
<br />
=== Credits ===<br />
<br />
''Justin D. Cockett - G8YTZ''<br />
<br />
[[Category:DATV]]<br />
[[Category:Receivers]]</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=Lynx_RPi5_Dual_RX&diff=12647Lynx RPi5 Dual RX2026-07-27T15:09:47Z<p>G8YTZ: </p>
<hr />
<div>== Lynx and Knobler ==<br />
<br />
'''Lynx''' is a Raspberry Pi-based control and monitoring package for amateur DATV reception, and '''Knobler''' is its companion hardware remote — a small rotary-dial display unit built on the M5Stack M5Dial. Together they turn a Picotuner-based DATV receiver into a system you can watch and control without a laptop or the Pi's own web UI open in front of you.<br />
<br />
This page gives a brief overview of both. See [[#Getting_Started|Getting Started]] below for setup instructions.<br />
<br />
=== Get Started ===<br />
<br />
* '''Lynx''' — [https://github.com/G8YTZ/lynx-datv-receiver source code, install guide, and full documentation]<br />
* '''Knobler''' — [https://github.com/G8YTZ/lynx-knobler source code]<br />
* New to Lynx? The [https://github.com/G8YTZ/lynx-datv-receiver/raw/main/docs/lynx_install_guide.docx Installation Guide] takes you from a blank SD card to a working receiver, including a one-line installer.<br />
<br />
=== Lynx ===<br />
<br />
Lynx runs on a Raspberry Pi and sits between the Picotuner hardware and the operator, providing:<br />
<br />
* A local web UI (default port 8080) for status, tuning, and configuration<br />
* Live decode status — lock state, MER, and related quality metrics, read from the Picotuner's status broadcast<br />
* A preset system for quickly recalling known frequencies/symbol rates across plugs (including saved presets created from the web UI)<br />
* Optional receive diversity combining across two tuner inputs, with automatic MER-based switching and a "hard freeze breaker" safeguard against repeated lock loss<br />
* Optional notifications — Slack, QRZ logbook lookups, and GPIO-triggered outputs (e.g. driving an external "on air" indicator) — each independently configurable and disabled by default<br />
* Optional RTMP relay of the decoded stream<br />
<br />
Configuration lives in a single YAML file covering site details (callsign, locator, location), the Picotuner connection, presets, streams, diversity settings, and notification integrations.<br />
<br />
Full documentation, including an install guide, a Web UI reference, and a guide to the on-screen display, is kept alongside the source: [https://github.com/G8YTZ/lynx-datv-receiver/tree/main/docs docs folder on GitHub].<br />
<br />
=== Knobler ===<br />
<br />
Knobler is a physical companion display for Lynx, built on an [https://docs.m5stack.com/en/core/M5Dial M5Stack M5Dial] — a small ESP32-based device with a round touchscreen and a rotary encoder. It polls Lynx's web API directly and gives you a dedicated, always-on physical readout and control surface, separate from the web UI.<br />
<br />
'''Current capabilities:'''<br />
<br />
* Live status display (lock state, signal quality) with a configurable poll interval<br />
* A menu system for browsing and selecting presets and streams via the rotary encoder, with an auto-timeout back to the normal display<br />
* Self-service Wi-Fi setup — no need to hardcode network credentials into the firmware or edit code to get it on your network (see below)<br />
* Automatic discovery of the Lynx receiver on the local network — no need to hardcode or manually enter an IP address<br />
<br />
==== Wi-Fi Setup ====<br />
<br />
On first boot (or if it can't find a previously-saved network), Knobler opens a temporary Wi-Fi access point of its own and displays a short prompt on screen. Connecting a phone or laptop to that access point brings up a normal Wi-Fi configuration page, where you select your network from a list and type in the password on a proper keyboard — rather than fumbling through SSID entry on a 1.28" touchscreen.<br />
<br />
Once configured, credentials are saved on the device. If the saved network ever becomes unreachable (moved out of range, router replaced, etc.), Knobler automatically falls back into setup mode after a short timeout, without any need to reflash or reconfigure it by hand.<br />
<br />
==== Auto-Discovery ====<br />
<br />
Rather than requiring a fixed, manually-entered IP address for the Lynx receiver, Knobler broadcasts a small discovery request on the local network on startup. Any Lynx instance running current software answers directly, providing its name, callsign, IP address, and API port — so Knobler finds the right receiver automatically, even if its address changes (e.g. after a router reboot hands out a new DHCP lease).<br />
<br />
=== Getting Started ===<br />
<br />
'''Requirements:'''<br />
<br />
* An M5Stack M5Dial device and USB-C cable<br />
* Arduino IDE, with ESP32/M5Stack board support and the required libraries (M5Dial, WiFiManager, ArduinoJson) installed<br />
* A Lynx receiver running current software (the discovery responder must be present — see below)<br />
* A computer or phone to complete Wi-Fi setup<br />
<br />
'''Lynx:''' the [https://github.com/G8YTZ/lynx-datv-receiver/raw/main/docs/lynx_install_guide.docx Installation Guide] covers everything from a blank SD card to a working receiver, including a one-line installer script.<br />
<br />
'''Before flashing Knobler:''' make sure the Lynx receiver is running a version of the software that includes the discovery responder (it prints a line similar to <code>Discovery responder listening on UDP :9998.</code> on startup). Older Lynx installs will need updating first, or Knobler won't be able to find them automatically.<br />
<br />
A full step-by-step Knobler installation guide — covering Arduino IDE setup, board/library installation, flashing, and first-time Wi-Fi configuration — is not yet published separately; for now, see the [https://github.com/G8YTZ/lynx-knobler Knobler repository] directly.<br />
<br />
=== Status ===<br />
<br />
Both projects are under active development. Known limitations at time of writing:<br />
<br />
* If more than one Lynx receiver answers a discovery request on the same network, Knobler currently connects to whichever reply arrives first — a picker screen for choosing between multiple receivers is planned but not yet built.<br />
* There is currently no on-device way to force Knobler back into Wi-Fi setup mode (e.g. to deliberately switch networks) short of clearing its saved credentials via a computer.<br />
<br />
=== See Also ===<br />
<br />
* [https://github.com/G8YTZ/lynx-datv-receiver Lynx source code and documentation on GitHub]<br />
* [https://github.com/G8YTZ/lynx-knobler Knobler source code on GitHub]<br />
* [[Picotuner]]<br />
<br />
=== Credits ===<br />
<br />
''Justin D. Cockett - G8YTZ''<br />
<br />
[[Category:DATV]]<br />
[[Category:Receivers]]</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12643GB3OO2026-07-24T10:37:40Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice tower)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice tower: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the tower.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
<div style="clear:both;"></div><br />
<br />
== Exciter Shelf ==<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v5 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
== ATEM Streaming Watchdog ==<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12642GB3OO2026-07-24T10:17:26Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice tower)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice tower: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the tower.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
<div style="clear:both;"></div><br />
<br />
== Exciter Shelf ==<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
== ATEM Streaming Watchdog ==<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=UK_ATV_repeaters&diff=12641UK ATV repeaters2026-07-24T08:58:44Z<p>G8YTZ: </p>
<hr />
<div>There are over 30 active ATV repeaters in the UK and the current status and operating frequencies can be found on the [https://www.ukrepeater.net/repeaterlist5.htm RSGB ETCC TV list]<br />
<br />
Here are two printable .pdf maps of TV Repeaters in the North and South of England: [[:Media:RptrNorth.pdf|Repeaters North]], [[:Media:RptrSouth.pdf|Repeaters South]]. These can be printed double-sided, landscape, flipped on the short edge.<br />
<br />
You can watch most UK ATV repeaters on the [http://www.batc.tv/ch_live.php BATC video streaming service.] <br />
<br />
[[File:tvrepeaters.JPG|400px]]<br />
<br />
All repeaters have a seperate page which the group can now edit to add information.<br />
<br />
*[[GB3AT]]<br />
<br />
*[[GB3BH]]<br />
<br />
*[[GB3CT - Caistor IO93UM]]<br />
<br />
*[[GB3ET]]<br />
<br />
*[[GB3EN - North London]]<br />
<br />
*[[GB3EY - Near Hull IO93RS]]<br />
<br />
*[[GB3FT]]<br />
<br />
*[[GB3GG]]<br />
<br />
*[[GB3GV]]<br />
<br />
*[[GB3HV]]<br />
<br />
*[[GB3JT]]<br />
<br />
*[[GB3JV]]<br />
<br />
*[[GB3KM]]<br />
<br />
*[[GB3LO]]<br />
<br />
*[[GB3LX]]<br />
<br />
*[[GB3NQ]]<br />
<br />
*[[GB3NV]]<br />
<br />
*[[GB3OO]] Folkestone - JO01NH<br />
<br />
*[[GB3PV]] Cambridge<br />
<br />
*[[GB3SQ]] Bournemouth<br />
<br />
*[[GB3TM]]<br />
<br />
*[[GB3TN]]<br />
<br />
*[[GB3TT - Sheffield IO93gk]]<br />
<br />
*[[GB3UD]]<br />
<br />
*[[GB3UT]]<br />
<br />
*[[GB3YT]]<br />
<br />
*[[GB3VL]]<br />
<br />
*[[GB3ZZ]]</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12640GB3OO2026-07-24T08:53:55Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice tower)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice tower: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
<div style="clear:both;"></div><br />
<br />
== Exciter Shelf ==<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
== ATEM Streaming Watchdog ==<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12639GB3OO2026-07-24T08:53:21Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice tower)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
<div style="clear:both;"></div><br />
<br />
== Exciter Shelf ==<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
== ATEM Streaming Watchdog ==<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12638GB3OO2026-07-24T08:51:17Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice mast)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
<div style="clear:both;"></div><br />
<br />
== Exciter Shelf ==<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
== ATEM Streaming Watchdog ==<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12637GB3OO2026-07-24T08:50:03Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice mast)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
<div style="clear:both;"></div><br />
<br />
== Exciter Shelf ==<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
=== ATEM Streaming Watchdog ===<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12636GB3OO2026-07-24T08:47:34Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice mast)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
<div style="clear:both;"></div><br />
<br />
=== Exciter Shelf ===<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
=== ATEM Streaming Watchdog ===<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12635GB3OO2026-07-24T08:46:12Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice mast)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
{{clear}}<br />
<br />
=== Exciter Shelf ===<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
=== ATEM Streaming Watchdog ===<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12634GB3OO2026-07-24T08:42:30Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Folkestone, Kent.<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice mast)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
=== Exciter Shelf ===<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v5 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
=== ATEM Streaming Watchdog ===<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12633GB3OO2026-07-24T08:37:57Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice mast)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
=== Exciter Shelf ===<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v5 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
=== ATEM Streaming Watchdog ===<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12632GB3OO2026-07-24T08:31:39Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice mast)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
=== Exciter Shelf ===<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
=== ATEM Streaming Watchdog ===<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12631GB3OO2026-07-24T08:29:31Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice mast)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
=== Exciter Shelf ===<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
=== ATEM Streaming Watchdog ===<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
The GB3OO test card was developed with the assistance of Claude AI, generated as an SVG graphic and tailored specifically for DATV use rather than adapted from a generic broadcast template.<br />
<br />
The card includes several purpose-built technical reference elements, mirrored on both the left and right sides for easy assessment regardless of framing:<br />
<br />
* '''Frequency gratings at three resolutions''' — fine vertical line gratings sized for 1920×1080p (2.00px line width), 1280×720p (3.00px), and 1024×576p (3.75px), allowing viewers to judge effective resolution and detect aliasing or softness at FHD, HD, and SD respectively, whichever the receiving chain is actually delivering.<br />
* '''EBU colour bars''' — the standard broadcast colour reference, useful for checking colour balance and saturation through the transmit and receive chain.<br />
* '''Monochrome (greyscale) staircase''' — an 8-step greyscale ramp for checking tonal linearity and spotting clipping or crushing at the black or white end of the range.<br />
<br />
The central animated graphic and "GB3OO" wordmark give the card a distinct identity, while the surrounding technical elements keep it functional as a genuine alignment and diagnostic tool rather than purely decorative.<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12630GB3OO2026-07-24T08:26:21Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice mast)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|right|400px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|left|400px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|right|400px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|left|350px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
=== Exciter Shelf ===<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
=== ATEM Streaming Watchdog ===<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|right|350px|GB3OO test card.]]<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12629GB3OO2026-07-24T08:23:27Z<p>G8YTZ: </p>
<hr />
<div>'''GB3OO''' is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
{| class="wikitable"<br />
! Location || Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
|-<br />
! Locator || JO01NC<br />
|-<br />
! NoV Holder || Justin D. Cockett, G8YTZ<br />
|-<br />
! Website || [https://gb3oo.co.uk gb3oo.co.uk]<br />
|}<br />
<br />
== Quick Reference ==<br />
<br />
{| class="wikitable"<br />
! Parameter !! Value<br />
|-<br />
| '''23cm Output''' || 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP<br />
|-<br />
| '''70cm Input''' || 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC<br />
|-<br />
| '''2m Talkback Input''' || 144.750 MHz FM, vertical, CTCSS 103.5 Hz<br />
|-<br />
| '''Web Stream (out)''' || <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
|-<br />
| '''Web Stream (in)''' || Registered users only — see gb3oo.co.uk "Streamer" page<br />
|-<br />
| '''Antenna height''' || 30 m (self-supporting lattice mast)<br />
|-<br />
| '''Tx antenna gain''' || 12 dBi (slotted waveguide, PE1RKI design)<br />
|}<br />
<br />
== Site Overview ==<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
[[File:GB3OO_Tx_and_Rx_Antennas.jpg|thumb|center|500px|The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.]]<br />
<br />
== Coverage ==<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
[[File:GB3OO_23cm_Coverage_Area.png|thumb|center|500px|Predicted 23cm coverage (green = strong signal, yellow = marginal).]]<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
[[File:GB3OO_70cm_Receive_Coverage_Area.png|thumb|center|500px|Predicted 70cm receive coverage.]]<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
== Transmit Chain ==<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
* '''Feeder run:''' 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
* '''Connectors:''' 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
* '''Antenna:''' Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
* '''Result:''' 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
* '''Return loss at commissioning:''' 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
== 70cm Receive Chain ==<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
# '''Interdigital bandpass filter''' (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
# '''Low-noise preamplifier''' (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
# '''SAW filter''' — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
# '''BATC Minitiouner''' DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
== Equipment Rack ==<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
[[File:GB3OO_Rack.jpg|thumb|center|400px|GB3OO equipment rack.]]<br />
<br />
'''Rack layout (bottom to top):'''<br />
<br />
{| class="wikitable"<br />
! RU !! Contents<br />
|-<br />
| 1 || Cable management brush strip<br />
|-<br />
| 2 || Raspberry Pi shelf — media player, stream receiver, 70cm receiver<br />
|-<br />
| 3 || Network equipment — UniFi UCG firewall, 7-port PoE switch<br />
|-<br />
| 4 || Windows 11 PC — Bitfocus Companion software, VLC for audio announcements<br />
|-<br />
| 5 || Mains distribution 2 (low-power devices)<br />
|-<br />
| 6 || Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage<br />
|-<br />
| 7–8 || Receiver shelf — BATC Minitiouner<br />
|-<br />
| 9–10 || HF modulator, H.264 encoder, Modbus TCP/RTU telemetry<br />
|-<br />
| 11–12 || Ventilation panel<br />
|-<br />
| 13–15 || Power amplifier<br />
|-<br />
| 16 || Cable management brush strip<br />
|-<br />
| 17 || Air-tight blanking panel<br />
|-<br />
| 18 || Mains distribution 1 (PA, exciter, case fans)<br />
|}<br />
<br />
=== Exciter Shelf ===<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
* '''Temperature sensors (PTC):''' exciter air outlet, PA air outlet, PA heatsink<br />
* '''Digital relay outputs:''' exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
* '''Analogue input:''' PA forward power<br />
* '''Digital output:''' PA power switching (local relays in the PA shelf)<br />
<br />
== Power & Infrastructure ==<br />
<br />
* '''UPS:''' APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
* '''Metering:''' A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
* '''UPS battery life:''' expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
== Licensing & Insurance ==<br />
<br />
* '''Ofcom:''' Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
* '''Software:''' All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
* '''Insurance:''' Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
== Control & Streaming Infrastructure ==<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
=== ATEM Streaming Watchdog ===<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
== Receiving GB3OO ==<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
'''What you need:'''<br />
* A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
* A standard '''HD''' satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
* A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
'''Receiver settings:'''<br />
<br />
{| class="wikitable"<br />
! Setting !! Value<br />
|-<br />
| LNB Local Oscillator || 9750 MHz<br />
|-<br />
| Symbol Rate || 2000 kSym/s (2 MSym/s)<br />
|-<br />
| Polarisation || Either — controls amplifier supply voltage, not signal<br />
|-<br />
| 22kHz Tone || OFF<br />
|-<br />
| LNB Power || ON<br />
|-<br />
| DiSEqC || OFF<br />
|}<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
== Test Card ==<br />
<br />
[[File:GB3OO_Test_Card.png|thumb|center|400px|GB3OO test card.]]<br />
<br />
== History / Timeline ==<br />
<br />
{| class="wikitable"<br />
! Date !! Milestone<br />
|-<br />
| 16 Sep 2025 || Website goes live; frequencies agreed<br />
|-<br />
| 8 Oct 2025 || Rack build underway — controller and receivers installed<br />
|-<br />
| 9 Oct 2025 || ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin<br />
|-<br />
| 15 May 2026 || Antenna installation complete<br />
|-<br />
| 21–22 May 2026 || Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational<br />
|-<br />
| 12 Jun 2026 || '''GB3OO officially on the air''' — 1304 MHz, 2 MSym/s, FEC 3/4<br />
|-<br />
| 14 Jun 2026 || 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks)<br />
|}<br />
<br />
== Membership & Community ==<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
* '''Session Recordings''' ("Time Machine") — rewind and catch up on missed activity<br />
* '''Repeater Control Portal''' — a live dashboard for repeater control<br />
* '''Slack Notifications''' — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
== Links ==<br />
<br />
* Website: [https://gb3oo.co.uk gb3oo.co.uk]<br />
* Coverage maps: [https://gb3oo.co.uk/predicted-coverage-map/ gb3oo.co.uk/predicted-coverage-map]<br />
* Streamer / reception instructions: [https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/ gb3oo.co.uk/receiving-the-gb3jv-network-stream]<br />
* Logbook: [https://gb3oo.co.uk/logbook/ gb3oo.co.uk/logbook]<br />
* BATC: [https://batc.org.uk batc.org.uk]<br />
* Direct web stream: <code>rtmp://rtmp.batc.org.uk/live/gb3oo</code><br />
<br />
----<br />
''This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let Justin, G8YTZ know if you'd like any of those expanded.''</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=File:GB3OO_Tx_and_Rx_Antennas.jpg&diff=12628File:GB3OO Tx and Rx Antennas.jpg2026-07-24T08:22:26Z<p>G8YTZ: File uploaded with MsUpload</p>
<hr />
<div>File uploaded with MsUpload</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=File:GB3OO_Test_Card.png&diff=12627File:GB3OO Test Card.png2026-07-24T08:22:26Z<p>G8YTZ: File uploaded with MsUpload</p>
<hr />
<div>File uploaded with MsUpload</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=File:GB3OO_Rack.jpg&diff=12626File:GB3OO Rack.jpg2026-07-24T08:22:24Z<p>G8YTZ: File uploaded with MsUpload</p>
<hr />
<div>File uploaded with MsUpload</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=File:GB3OO_70cm_Receive_Coverage_Area.png&diff=12625File:GB3OO 70cm Receive Coverage Area.png2026-07-24T08:22:23Z<p>G8YTZ: File uploaded with MsUpload</p>
<hr />
<div>File uploaded with MsUpload</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=File:GB3OO_23cm_Coverage_Area.png&diff=12624File:GB3OO 23cm Coverage Area.png2026-07-24T08:22:21Z<p>G8YTZ: File uploaded with MsUpload</p>
<hr />
<div>File uploaded with MsUpload</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12623GB3OO2026-07-24T08:18:36Z<p>G8YTZ: Blanked the page</p>
<hr />
<div></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3OO&diff=12622GB3OO2026-07-24T08:17:44Z<p>G8YTZ: Created page with "# GB3OO — Digital Amateur Television Repeater **Location:** Upper Arpinge, near Folkestone, Kent, CT18 8AD **Locator:** JO01NC **NoV Holder:** Justin D. Cockett, G8YTZ **We..."</p>
<hr />
<div># GB3OO — Digital Amateur Television Repeater<br />
<br />
**Location:** Upper Arpinge, near Folkestone, Kent, CT18 8AD<br />
**Locator:** JO01NC<br />
**NoV Holder:** Justin D. Cockett, G8YTZ<br />
**Website:** [gb3oo.co.uk](https://gb3oo.co.uk)<br />
<br />
GB3OO is a Digital Amateur Television (DATV) repeater serving the amateur radio community across Kent, Essex, and the near continent. It went fully on air on 12 June 2026, transmitting on 23cm with a 70cm input, and streams its output live to the internet via the BATC.<br />
<br />
---<br />
<br />
## Quick Reference<br />
<br />
| Parameter | Value |<br />
|---|---|<br />
| **23cm Output** | 1304 MHz, DVB-S2, 2 MSym/s, FEC 3/4, roll-off 0.35, 150W EIRP |<br />
| **70cm Input** | 437 MHz, DVB-S/S2, 333 kSym/s, automatic FEC |<br />
| **2m Talkback Input** | 144.750 MHz FM, vertical, CTCSS 103.5 Hz |<br />
| **Web Stream (out)** | `rtmp://rtmp.batc.org.uk/live/gb3oo` |<br />
| **Web Stream (in)** | Registered users only — see gb3oo.co.uk "Streamer" page |<br />
| **Antenna height** | 30 m (self-supporting lattice mast) |<br />
| **Tx antenna gain** | 12 dBi (slotted waveguide, PE1RKI design) |<br />
<br />
---<br />
<br />
## Site Overview<br />
<br />
GB3OO sits at a rural hilltop location near Folkestone, chosen for its excellent coverage across the surrounding area. The installation is built around a self-supporting lattice mast: at the summit, the 23cm slotted-waveguide transmit antenna and the 70cm "Big Wheel" receive antenna are mounted together. A brick-built equipment building at the base of the tower houses the full repeater rack.<br />
<br />
<br />
<br />
*The 23cm slotted waveguide (white panel) and 70cm Big Wheel receive antenna at the top of the mast.*<br />
<br />
---<br />
<br />
## Coverage<br />
<br />
GB3OO's 23cm output covers a large area of Kent, Essex, London, and across the Channel into northern France and Belgium — conditions permitting, and especially well during tropospheric ducting.<br />
<br />
<br />
<br />
*Predicted 23cm coverage (green = strong signal, yellow = marginal).*<br />
<br />
The 70cm receive input has a correspondingly wide catchment for stations wanting to transmit into the repeater, fed by an omnidirectional dual-stack WIMO "Big Wheel" antenna (5 dBi gain).<br />
<br />
<br />
<br />
During good tropo conditions, continental stations from France, Belgium, and beyond are actively welcomed — the repeater's French-language announcement specifically invites this.<br />
<br />
---<br />
<br />
## Transmit Chain<br />
<br />
The transmit chain starts at the power amplifier, delivering 10W RF output at 23cm.<br />
<br />
- **Feeder run:** 4m LDF5-50 7/8" Heliax tail → 30m LDF6-50 1-5/8" Heliax main run (the larger diameter minimises loss over the long vertical run) → 2m LDF5-50 tail to the antenna feed point<br />
- **Connectors:** 7/16 DIN throughout (chosen over N-type for low loss and superior intermodulation performance at these power levels)<br />
- **Antenna:** Slotted waveguide, designed and built by Bert Moderman (PE1RKI) — seven radiating slots per face on two faces, giving an omnidirectional azimuth pattern within ±1.3 dB and 12 dBi gain<br />
- **Result:** 150W EIRP, meeting the licensed limit once feeder and coupler losses are accounted for<br />
- **Return loss at commissioning:** 30.5 dB — an excellent match, important at 23cm since poor return loss on a long feeder causes standing-wave echoes that visibly degrade DVB-S2 signal quality (closing the constellation "eye," raising EVM, lowering MER)<br />
<br />
## 70cm Receive Chain<br />
<br />
The receive chain is built for strong out-of-band rejection given the site's exposure to cellular and other nearby services:<br />
<br />
1. **Interdigital bandpass filter** (Bert Moderman, PE1RKI) — first-stage protection against strong out-of-band signals<br />
2. **Low-noise preamplifier** (also PE1RKI) — 15 dB gain, 0.35 dB noise figure, setting the noise floor for the whole receive chain<br />
3. **SAW filter** — ~60 dB attenuation at 470 MHz, eliminating interference from terrestrial digital TV and UHF PMR<br />
4. **BATC Minitiouner** DVB-S/S2 tuner running the Ryde Receiver for demodulation<br />
<br />
Since interdigital filters have responses at odd harmonics, the second filtering stage (the SAW filter) is essential to fully clean up the signal before demodulation.<br />
<br />
---<br />
<br />
## Equipment Rack<br />
<br />
The repeater is housed in a wall-mounted 19" × 450mm(d) × 18U rack with removable side panels and a lockable glass front door. Two continuously-running 240V axial fans provide cooling, with heavy electrical loads mounted toward the top to keep a cool zone at the bottom of the cabinet.<br />
<br />
<br />
<br />
**Rack layout (bottom to top):**<br />
<br />
| RU | Contents |<br />
|---|---|<br />
| 1 | Cable management brush strip |<br />
| 2 | Raspberry Pi shelf — media player, stream receiver, 70cm receiver |<br />
| 3 | Network equipment — UniFi UCG firewall, 7-port PoE switch |<br />
| 4 | Windows 11 PC — Bitfocus Companion software, VLC for audio announcements |<br />
| 5 | Mains distribution 2 (low-power devices) |<br />
| 6 | Pull-out drawer — Blackmagic ATEM Mini Pro video switcher, 2m receiver, 1TB SSD local storage |<br />
| 7–8 | Receiver shelf — BATC Minitiouner |<br />
| 9–10 | HF modulator, H.264 encoder, Modbus TCP/RTU telemetry |<br />
| 11–12 | Ventilation panel |<br />
| 13–15 | Power amplifier |<br />
| 16 | Cable management brush strip |<br />
| 17 | Air-tight blanking panel |<br />
| 18 | Mains distribution 1 (PA, exciter, case fans) |<br />
<br />
### Exciter Shelf<br />
<br />
The modulator is an SR-Systems "Minimod" HF modulator paired with an SR-Systems H.264 encoder, managed via a VT-100 emulation RS-232 interface accessed over Telnet through an in-built terminal server on a fixed IP.<br />
<br />
The exciter shelf also carries the transmitter telemetry, via Modbus TCP/RTU:<br />
<br />
- **Temperature sensors (PTC):** exciter air outlet, PA air outlet, PA heatsink<br />
- **Digital relay outputs:** exciter load/PA co-ax relay, ATEM power on/off (cold reset only)<br />
- **Analogue input:** PA forward power<br />
- **Digital output:** PA power switching (local relays in the PA shelf)<br />
<br />
---<br />
<br />
## Power & Infrastructure<br />
<br />
- **UPS:** APC tower UPS, fed from a blue 16A "Commando" connector that also serves as the safety isolator. Emergency isolation is via removing the two 13A plug tops from the orange distribution board at the rear of the UPS.<br />
- **Metering:** A Modbus-compatible meter in the mains distribution board (located above the repeater) tracks electricity consumption.<br />
- **UPS battery life:** expected to need replacement around 5 years from commissioning (May 2026), usage-dependent.<br />
<br />
---<br />
<br />
## Licensing & Insurance<br />
<br />
- **Ofcom:** Licensed via Notice of Variation dated 30 September 2025, renewal due 29 September 2028. NoV holder: Justin D. Cockett (G8YTZ).<br />
- **Software:** All repeater system software is open-source or perpetually licensed. The PiDeck media player is licensed from Guy, M0GUY, and requires a continual internet connection to remain licensed. Commercial components (UniFi, Blackmagic ATEM, Windows 11) are licensed per manufacturer T&Cs.<br />
- **Insurance:** Covered under the RSGB's Repeater & Beacon insurance scheme, renewed annually each May by G8YTZ.<br />
<br />
---<br />
<br />
## Control & Streaming Infrastructure<br />
<br />
The site runs a Bitfocus Companion v4 control portal, giving webhook-triggered automatic input switching, an ATEM video switcher, and full session recording ("Time Machine") of repeater activity — all accessible to registered users via the website's Repeater Control Portal.<br />
<br />
### ATEM Streaming Watchdog<br />
<br />
The ATEM Mini Pro video switcher has a known Blackmagic firmware bug: after a power cycle, its streaming configuration (RTMP URL, key, bitrates) can come back corrupted, silently taking the stream offline. A custom Python watchdog runs continuously on the site PC, detecting this condition and automatically restoring the correct configuration — no site visit required. Full technical detail, installation procedure, and troubleshooting are covered in the separate ATEM Watchdog manual.<br />
<br />
---<br />
<br />
## Receiving GB3OO<br />
<br />
GB3OO can be received cheaply — often with equipment already owned. Full detail is on the website's "Streamer" and reception guide pages; in summary:<br />
<br />
**What you need:**<br />
- A small 23cm Yagi antenna (wideband version recommended; e.g. Antenna Amplifiers' 23cm5ra or 23cm13dxr) plus feeder<br />
- A standard **HD** satellite receiver — many modern TVs (LG, Samsung, Sony tested) have a suitable built-in tuner<br />
- A small in-line amplifier to compensate for 23cm cable losses<br />
<br />
**Receiver settings:**<br />
<br />
| Setting | Value |<br />
|---|---|<br />
| LNB Local Oscillator | 9750 MHz |<br />
| Symbol Rate | 2000 kSym/s (2 MSym/s) |<br />
| Polarisation | Either — controls amplifier supply voltage, not signal |<br />
| 22kHz Tone | OFF |<br />
| LNB Power | ON |<br />
| DiSEqC | OFF |<br />
<br />
Then run a blind scan — if signal is good, the receiver will find and add GB3OO automatically.<br />
<br />
Check the coverage map first; anyone in the "green" area with a clear line of sight toward Folkestone should have an easy time of it. Justin, G8YTZ, is happy to help assess individual locations (contact via QRZ).<br />
<br />
If an antenna isn't practical, streaming into the repeater from a phone or via OBS is also supported — see the "Streamer Key and Instructions" page on the website.<br />
<br />
---<br />
<br />
## Test Card<br />
<br />
<br />
<br />
---<br />
<br />
## History / Timeline<br />
<br />
| Date | Milestone |<br />
|---|---|<br />
| 16 Sep 2025 | Website goes live; frequencies agreed |<br />
| 8 Oct 2025 | Rack build underway — controller and receivers installed |<br />
| 9 Oct 2025 | ATEM switcher and network equipment delivered and configured; ad-hoc streaming tests begin |<br />
| 15 May 2026 | Antenna installation complete |<br />
| 21–22 May 2026 | Equipment installed on site at Folkestone; output streaming live; 70cm receiver operational |<br />
| 12 Jun 2026 | **GB3OO officially on the air** — 1304 MHz, 2 MSym/s, FEC 3/4 |<br />
| 14 Jun 2026 | 70cm receiver lock-detection improved (5-second confirm timer to eliminate false/short locks) |<br />
<br />
---<br />
<br />
## Membership & Community<br />
<br />
Registration on gb3oo.co.uk is free and unlocks:<br />
<br />
- **Session Recordings** ("Time Machine") — rewind and catch up on missed activity<br />
- **Repeater Control Portal** — a live dashboard for repeater control<br />
- **Slack Notifications** — alerts when the repeater comes into use<br />
<br />
Anyone registered on the GB3JV website as of 31 December 2025 has had their login carried across automatically; anyone else needs to register separately.<br />
<br />
---<br />
<br />
## Links<br />
<br />
- Website: [gb3oo.co.uk](https://gb3oo.co.uk)<br />
- Coverage maps: [gb3oo.co.uk/predicted-coverage-map](https://gb3oo.co.uk/predicted-coverage-map/)<br />
- Streamer / reception instructions: [gb3oo.co.uk/receiving-the-gb3jv-network-stream](https://gb3oo.co.uk/receiving-the-gb3jv-network-stream/)<br />
- Logbook: [gb3oo.co.uk/logbook](https://gb3oo.co.uk/logbook/)<br />
- BATC: [batc.org.uk](https://batc.org.uk)<br />
- Direct web stream: `rtmp://rtmp.batc.org.uk/live/gb3oo`<br />
<br />
---<br />
<br />
*This page draws on the GB3OO website, the GB3OO technical manual, and site documentation. Some sections (network/remote access IP plan, full control portal configuration, detailed component part numbers) are held in the restricted technical manual and are only summarised here — let me know if you'd like any of those expanded.*</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=UK_ATV_repeaters&diff=12621UK ATV repeaters2026-07-24T08:00:42Z<p>G8YTZ: </p>
<hr />
<div>There are over 30 active ATV repeaters in the UK and the current status and operating frequencies can be found on the [https://www.ukrepeater.net/repeaterlist5.htm RSGB ETCC TV list]<br />
<br />
Here are two printable .pdf maps of TV Repeaters in the North and South of England: [[:Media:RptrNorth.pdf|Repeaters North]], [[:Media:RptrSouth.pdf|Repeaters South]]. These can be printed double-sided, landscape, flipped on the short edge.<br />
<br />
You can watch most UK ATV repeaters on the [http://www.batc.tv/ch_live.php BATC video streaming service.] <br />
<br />
[[File:tvrepeaters.JPG|400px]]<br />
<br />
All repeaters have a seperate page which the group can now edit to add information.<br />
<br />
*[[GB3AT]]<br />
<br />
*[[GB3BH]]<br />
<br />
*[[GB3CT - Caistor IO93UM]]<br />
<br />
*[[GB3ET]]<br />
<br />
*[[GB3EN - North London]]<br />
<br />
*[[GB3EY - Near Hull IO93RS]]<br />
<br />
*[[GB3FT]]<br />
<br />
*[[GB3GG]]<br />
<br />
*[[GB3GV]]<br />
<br />
*[[GB3HV]]<br />
<br />
*[[GB3JT]]<br />
<br />
*[[GB3JV]]<br />
<br />
*[[GB3KM]]<br />
<br />
*[[GB3LO]]<br />
<br />
*[[GB3LX]]<br />
<br />
*[[GB3NQ]]<br />
<br />
*[[GB3NV]]<br />
<br />
*[[GB3OO]] Folkestone<br />
<br />
*[[GB3PV]] Cambridge<br />
<br />
*[[GB3SQ]] Bournemouth<br />
<br />
*[[GB3TM]]<br />
<br />
*[[GB3TN]]<br />
<br />
*[[GB3TT - Sheffield IO93gk]]<br />
<br />
*[[GB3UD]]<br />
<br />
*[[GB3UT]]<br />
<br />
*[[GB3YT]]<br />
<br />
*[[GB3VL]]<br />
<br />
*[[GB3ZZ]]</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=Lynx_RPi5_Dual_RX&diff=12620Lynx RPi5 Dual RX2026-07-22T08:17:37Z<p>G8YTZ: </p>
<hr />
<div>= Lynx and Knobler =<br />
<br />
'''Lynx''' is a Raspberry Pi-based control and monitoring package for amateur DATV reception, and '''Knobler''' is its companion hardware remote — a small rotary-dial display unit built on the M5Stack M5Dial. Together they turn a Picotuner-based DATV receiver into a system you can watch and control without a laptop or the Pi's own web UI open in front of you.<br />
<br />
This page gives a brief overview of both. See the [[#Getting Started|Getting Started]] section below for setup instructions.<br />
<br />
== Lynx ==<br />
<br />
Lynx runs on a Raspberry Pi and sits between the Picotuner hardware and the operator, providing:<br />
<br />
* A local web UI (default port 8080) for status, tuning, and configuration<br />
* Live decode status — lock state, MER, and related quality metrics, read from the Picotuner's status broadcast<br />
* A preset system for quickly recalling known frequencies/symbol rates across plugs (including saved presets created from the web UI)<br />
* Optional receive diversity combining across two tuner inputs, with automatic MER-based switching and a "hard freeze breaker" safeguard against repeated lock loss<br />
* Optional notifications — Slack, QRZ logbook lookups, and GPIO-triggered outputs (e.g. driving an external "on air" indicator) — each independently configurable and disabled by default<br />
* Optional RTMP relay of the decoded stream<br />
<br />
Configuration lives in a single YAML file covering site details (callsign, locator, location), the Picotuner connection, presets, streams, diversity settings, and notification integrations.<br />
<br />
== Knobler ==<br />
<br />
Knobler is a physical companion display for Lynx, built on an [https://docs.m5stack.com/en/core/M5Dial M5Stack M5Dial] — a small ESP32-based device with a round touchscreen and a rotary encoder. It polls Lynx's web API directly and gives you a dedicated, always-on physical readout and control surface, separate from the web UI.<br />
<br />
'''Current capabilities:'''<br />
<br />
* Live status display (lock state, signal quality) with a configurable poll interval<br />
* A menu system for browsing and selecting presets and streams via the rotary encoder, with an auto-timeout back to the normal display<br />
* Self-service Wi-Fi setup — no need to hardcode network credentials into the firmware or edit code to get it on your network (see below)<br />
* Automatic discovery of the Lynx receiver on the local network — no need to hardcode or manually enter an IP address<br />
<br />
=== Wi-Fi Setup ===<br />
<br />
On first boot (or if it can't find a previously-saved network), Knobler opens a temporary Wi-Fi access point of its own and displays a short prompt on screen. Connecting a phone or laptop to that access point brings up a normal Wi-Fi configuration page, where you select your network from a list and type in the password on a proper keyboard — rather than fumbling through SSID entry on a 1.28" touchscreen.<br />
<br />
Once configured, credentials are saved on the device. If the saved network ever becomes unreachable (moved out of range, router replaced, etc.), Knobler automatically falls back into setup mode after a short timeout, without any need to reflash or reconfigure it by hand.<br />
<br />
=== Auto-Discovery ===<br />
<br />
Rather than requiring a fixed, manually-entered IP address for the Lynx receiver, Knobler broadcasts a small discovery request on the local network on startup. Any Lynx instance running current software answers directly, providing its name, callsign, IP address, and API port — so Knobler finds the right receiver automatically, even if its address changes (e.g. after a router reboot hands out a new DHCP lease).<br />
<br />
== Getting Started ==<br />
<br />
'''Requirements:'''<br />
* An M5Stack M5Dial device and USB-C cable<br />
* Arduino IDE, with ESP32/M5Stack board support and the required libraries (M5Dial, WiFiManager, ArduinoJson) installed<br />
* A Lynx receiver running current software (the discovery responder must be present — see below)<br />
* A computer or phone to complete Wi-Fi setup<br />
<br />
'''Before flashing Knobler:''' make sure the Lynx receiver is running a version of the software that includes the discovery responder (it prints a line similar to <code>Discovery responder listening on UDP :9998.</code> on startup). Older Lynx installs will need updating first, or Knobler won't be able to find them automatically.<br />
<br />
A full step-by-step installation guide — covering Arduino IDE setup, board/library installation, flashing, and first-time Wi-Fi configuration — is available separately: '''[insert link to installation guide here]'''.<br />
<br />
== Status ==<br />
<br />
Both projects are under active development. Known limitations at time of writing:<br />
<br />
* If more than one Lynx receiver answers a discovery request on the same network, Knobler currently connects to whichever reply arrives first — a picker screen for choosing between multiple receivers is planned but not yet built.<br />
* There is currently no on-device way to force Knobler back into Wi-Fi setup mode (e.g. to deliberately switch networks) short of clearing its saved credentials via a computer.<br />
<br />
== See Also ==<br />
<br />
* [link to Lynx source/repository - coming soon!]<br />
* [link to Knobler source/repository - coming soon!]<br />
* [[Picotuner]]<br />
<br />
== Credits ==<br />
<br />
''[Justin D. Cockett - G8YTZ]''<br />
<br />
[[Category:DATV]]<br />
[[Category:Receivers]]</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=Lynx_RPi5_Dual_RX&diff=12619Lynx RPi5 Dual RX2026-07-22T06:26:08Z<p>G8YTZ: /* Credits */</p>
<hr />
<div>= Lynx and Knobler =<br />
<br />
'''Lynx''' is a Raspberry Pi-based control and monitoring package for amateur DATV reception, and '''Knobler''' is its companion hardware remote — a small rotary-dial display unit built on the M5Stack M5Dial. Together they turn a Picotuner-based DATV receiver into a system you can watch and control without a laptop or the Pi's own web UI open in front of you.<br />
<br />
This page gives a brief overview of both. See the [[#Getting Started|Getting Started]] section below for setup instructions.<br />
<br />
== Lynx ==<br />
<br />
Lynx runs on a Raspberry Pi and sits between the Picotuner hardware and the operator, providing:<br />
<br />
* A local web UI (default port 8080) for status, tuning, and configuration<br />
* Live decode status — lock state, MER, and related quality metrics, read from the Picotuner's status broadcast<br />
* A preset system for quickly recalling known frequencies/symbol rates across plugs (including saved presets created from the web UI)<br />
* Optional receive diversity combining across two tuner inputs, with automatic MER-based switching and a "hard freeze breaker" safeguard against repeated lock loss<br />
* Optional notifications — Slack, QRZ logbook lookups, and GPIO-triggered outputs (e.g. driving an external "on air" indicator) — each independently configurable and disabled by default<br />
* Optional RTMP relay of the decoded stream<br />
<br />
Configuration lives in a single YAML file covering site details (callsign, locator, location), the Picotuner connection, presets, streams, diversity settings, and notification integrations.<br />
<br />
== Knobler ==<br />
<br />
Knobler is a physical companion display for Lynx, built on an [https://docs.m5stack.com/en/core/M5Dial M5Stack M5Dial] — a small ESP32-based device with a round touchscreen and a rotary encoder. It polls Lynx's web API directly and gives you a dedicated, always-on physical readout and control surface, separate from the web UI.<br />
<br />
'''Current capabilities:'''<br />
<br />
* Live status display (lock state, signal quality) with a configurable poll interval<br />
* A menu system for browsing and selecting presets and streams via the rotary encoder, with an auto-timeout back to the normal display<br />
* Self-service Wi-Fi setup — no need to hardcode network credentials into the firmware or edit code to get it on your network (see below)<br />
* Automatic discovery of the Lynx receiver on the local network — no need to hardcode or manually enter an IP address<br />
<br />
=== Wi-Fi Setup ===<br />
<br />
On first boot (or if it can't find a previously-saved network), Knobler opens a temporary Wi-Fi access point of its own and displays a short prompt on screen. Connecting a phone or laptop to that access point brings up a normal Wi-Fi configuration page, where you select your network from a list and type in the password on a proper keyboard — rather than fumbling through SSID entry on a 1.28" touchscreen.<br />
<br />
Once configured, credentials are saved on the device. If the saved network ever becomes unreachable (moved out of range, router replaced, etc.), Knobler automatically falls back into setup mode after a short timeout, without any need to reflash or reconfigure it by hand.<br />
<br />
=== Auto-Discovery ===<br />
<br />
Rather than requiring a fixed, manually-entered IP address for the Lynx receiver, Knobler broadcasts a small discovery request on the local network on startup. Any Lynx instance running current software answers directly, providing its name, callsign, IP address, and API port — so Knobler finds the right receiver automatically, even if its address changes (e.g. after a router reboot hands out a new DHCP lease).<br />
<br />
== Getting Started ==<br />
<br />
'''Requirements:'''<br />
* An M5Stack M5Dial device and USB-C cable<br />
* Arduino IDE, with ESP32/M5Stack board support and the required libraries (M5Dial, WiFiManager, ArduinoJson) installed<br />
* A Lynx receiver running current software (the discovery responder must be present — see below)<br />
* A computer or phone to complete Wi-Fi setup<br />
<br />
'''Before flashing Knobler:''' make sure the Lynx receiver is running a version of the software that includes the discovery responder (it prints a line similar to <code>Discovery responder listening on UDP :9998.</code> on startup). Older Lynx installs will need updating first, or Knobler won't be able to find them automatically.<br />
<br />
A full step-by-step installation guide — covering Arduino IDE setup, board/library installation, flashing, and first-time Wi-Fi configuration — is available separately: '''[insert link to installation guide here]'''.<br />
<br />
== Status ==<br />
<br />
Both projects are under active development. Known limitations at time of writing:<br />
<br />
* If more than one Lynx receiver answers a discovery request on the same network, Knobler currently connects to whichever reply arrives first — a picker screen for choosing between multiple receivers is planned but not yet built.<br />
* There is currently no on-device way to force Knobler back into Wi-Fi setup mode (e.g. to deliberately switch networks) short of clearing its saved credentials via a computer.<br />
<br />
== See Also ==<br />
<br />
* [insert link to Lynx source/repository]<br />
* [insert link to Knobler source/repository]<br />
* [[Picotuner]]<br />
<br />
== Credits ==<br />
<br />
''[Justin D. Cockett - G8YTZ]''<br />
<br />
[[Category:DATV]]<br />
[[Category:Receivers]]</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=Lynx_RPi5_Dual_RX&diff=12618Lynx RPi5 Dual RX2026-07-22T06:25:18Z<p>G8YTZ: </p>
<hr />
<div>= Lynx and Knobler =<br />
<br />
'''Lynx''' is a Raspberry Pi-based control and monitoring package for amateur DATV reception, and '''Knobler''' is its companion hardware remote — a small rotary-dial display unit built on the M5Stack M5Dial. Together they turn a Picotuner-based DATV receiver into a system you can watch and control without a laptop or the Pi's own web UI open in front of you.<br />
<br />
This page gives a brief overview of both. See the [[#Getting Started|Getting Started]] section below for setup instructions.<br />
<br />
== Lynx ==<br />
<br />
Lynx runs on a Raspberry Pi and sits between the Picotuner hardware and the operator, providing:<br />
<br />
* A local web UI (default port 8080) for status, tuning, and configuration<br />
* Live decode status — lock state, MER, and related quality metrics, read from the Picotuner's status broadcast<br />
* A preset system for quickly recalling known frequencies/symbol rates across plugs (including saved presets created from the web UI)<br />
* Optional receive diversity combining across two tuner inputs, with automatic MER-based switching and a "hard freeze breaker" safeguard against repeated lock loss<br />
* Optional notifications — Slack, QRZ logbook lookups, and GPIO-triggered outputs (e.g. driving an external "on air" indicator) — each independently configurable and disabled by default<br />
* Optional RTMP relay of the decoded stream<br />
<br />
Configuration lives in a single YAML file covering site details (callsign, locator, location), the Picotuner connection, presets, streams, diversity settings, and notification integrations.<br />
<br />
== Knobler ==<br />
<br />
Knobler is a physical companion display for Lynx, built on an [https://docs.m5stack.com/en/core/M5Dial M5Stack M5Dial] — a small ESP32-based device with a round touchscreen and a rotary encoder. It polls Lynx's web API directly and gives you a dedicated, always-on physical readout and control surface, separate from the web UI.<br />
<br />
'''Current capabilities:'''<br />
<br />
* Live status display (lock state, signal quality) with a configurable poll interval<br />
* A menu system for browsing and selecting presets and streams via the rotary encoder, with an auto-timeout back to the normal display<br />
* Self-service Wi-Fi setup — no need to hardcode network credentials into the firmware or edit code to get it on your network (see below)<br />
* Automatic discovery of the Lynx receiver on the local network — no need to hardcode or manually enter an IP address<br />
<br />
=== Wi-Fi Setup ===<br />
<br />
On first boot (or if it can't find a previously-saved network), Knobler opens a temporary Wi-Fi access point of its own and displays a short prompt on screen. Connecting a phone or laptop to that access point brings up a normal Wi-Fi configuration page, where you select your network from a list and type in the password on a proper keyboard — rather than fumbling through SSID entry on a 1.28" touchscreen.<br />
<br />
Once configured, credentials are saved on the device. If the saved network ever becomes unreachable (moved out of range, router replaced, etc.), Knobler automatically falls back into setup mode after a short timeout, without any need to reflash or reconfigure it by hand.<br />
<br />
=== Auto-Discovery ===<br />
<br />
Rather than requiring a fixed, manually-entered IP address for the Lynx receiver, Knobler broadcasts a small discovery request on the local network on startup. Any Lynx instance running current software answers directly, providing its name, callsign, IP address, and API port — so Knobler finds the right receiver automatically, even if its address changes (e.g. after a router reboot hands out a new DHCP lease).<br />
<br />
== Getting Started ==<br />
<br />
'''Requirements:'''<br />
* An M5Stack M5Dial device and USB-C cable<br />
* Arduino IDE, with ESP32/M5Stack board support and the required libraries (M5Dial, WiFiManager, ArduinoJson) installed<br />
* A Lynx receiver running current software (the discovery responder must be present — see below)<br />
* A computer or phone to complete Wi-Fi setup<br />
<br />
'''Before flashing Knobler:''' make sure the Lynx receiver is running a version of the software that includes the discovery responder (it prints a line similar to <code>Discovery responder listening on UDP :9998.</code> on startup). Older Lynx installs will need updating first, or Knobler won't be able to find them automatically.<br />
<br />
A full step-by-step installation guide — covering Arduino IDE setup, board/library installation, flashing, and first-time Wi-Fi configuration — is available separately: '''[insert link to installation guide here]'''.<br />
<br />
== Status ==<br />
<br />
Both projects are under active development. Known limitations at time of writing:<br />
<br />
* If more than one Lynx receiver answers a discovery request on the same network, Knobler currently connects to whichever reply arrives first — a picker screen for choosing between multiple receivers is planned but not yet built.<br />
* There is currently no on-device way to force Knobler back into Wi-Fi setup mode (e.g. to deliberately switch networks) short of clearing its saved credentials via a computer.<br />
<br />
== See Also ==<br />
<br />
* [insert link to Lynx source/repository]<br />
* [insert link to Knobler source/repository]<br />
* [[Picotuner]]<br />
<br />
== Credits ==<br />
<br />
''[insert author/maintainer attribution here]''<br />
<br />
[[Category:DATV]]<br />
[[Category:Receivers]]</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=Lynx_RPi5_Dual_RX&diff=12617Lynx RPi5 Dual RX2026-07-21T15:24:09Z<p>G8YTZ: Alpha v0.e</p>
<hr />
<div>The Lynx receiver is a DATV receiver being developed by Justin G8YTZ. As of July 2026 it was in early prototype form and not released.<br />
<br />
The hardware includes a Raspberry Pi 5 with display, network connected to a PicoTuner with G4EWJ's ethernet interface.<br />
<br />
Features include diversity reception across the tuner's 2 inputs.<br />
<br />
Attached is the Alpha software for the “Pi 5 Lynx” DATV Receiver that I have been working on. You’ll need a Pi 5 with 4GB RAM and a 32GB SD card. In theory a 2GB Pi 5 will work, but will be come a problem as I add new features. PicoTuner with ethernet - latest code required.<br />
<br />
Known issue to be aware of: On first boot/tune in Diversity mode one tuners may not lock, we’ve implemented a workaround, by sending the tune command twice on boot, but the core issue seems that the PicoTuner cannot reliably cope with a second tune command whilst acquiring/locking the first signal.<br />
<br />
Readme Folder:<br />
<br />
Installation Instructions for the Alpha testers<br />
Web UI documentation - what all the bits do<br />
Lynx Features (quite old now, but sets the scene)<br />
Lynx Diversity manual - details of the Lynx Diversity feature and the journey so far.<br />
Lynx Diversity Progress Report - a bit historical now, but explains why we changed to PCR from packet sequence combining. My original idea was we could generate wall-clock sequence numbers by generating check sums from the packet sequence, but PCR was much simpler to implement.<br />
<br />
best regards<br />
<br />
Justin Cockett - G8YTZ</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9938GB3JV2022-07-10T21:59:31Z<p>G8YTZ: </p>
<hr />
<div><div><br />
<p><span style="color: #0000ff;"><strong>GB3JV DATV repeater located in Petts Wood, Kent</strong></span></p><br />
</div><br />
<div><br />
<p><strong><span style="color: #0000ff;">Output:</span> 3.404GHz - 2MS/s - DVBS-2 - 0.35 - FEC 4/5 - Horiz. Polarisation</strong></p><br />
</div><br />
<div><br />
<p><strong><span style="color: #0000ff;">Location:&nbsp;</span>JO01AJ (Petts Wood Railway Station)&nbsp;</strong></p><br />
<p><strong><span style="color: #0000ff;">Web Site: http://www.gb3jv.co.uk/<br />
</div><br />
<p><span style="color: #0000ff;"><strong>GB3JV Overview</strong></span></p><br />
<ul><br />
<li>The repeater uses an innovative new controller system based on the Blackmagic ATEM Mini Pro broadcast switcher and Bitfocus&rsquo; &ldquo;Companion&rdquo; middleware</li><br />
<li>The 70cm and 23cm receivers are based on the &ldquo;Minitiouner&rdquo; hardware, developed by F6DZP and the &ldquo;Ryde&rdquo; software developed by members of the BATC</li><br />
<li>When a signal is received a &ldquo;web-hook&rdquo; command is sent to &ldquo;Companion&rdquo; and sends an instruction to the ATEM that instigates a MACRO to transition to the active input</li><br />
<li>The web stream is generated by the ATEM Mini Pro and the media server is based on Guy, M0GUY&rsquo;s PiDeck software</li><br />
<li>You can register on the web site to receive a stream key and to be included in the GB3JV SLACK channel. SLACK will alert you to repeater activity so you can join in with a QSO.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Telemetry:</strong></span></p><br />
<p>The repeater&rsquo;s<span class="Apple-converted-space">&nbsp; </span>telemetry system is based on the &ldquo;Modbus RTU&rdquo; protocol over internet protocol this allows:</p><br />
<ul><br />
<li>Full remote monitoring of the repeater&rsquo;s health with notifications to the keeper&rsquo;s iPhone</li><br />
<li>Full remote control of the repeater&rsquo;s functions and status</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Outputs:</strong></span></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream: rtmp://rtmp.batc.org.uk/live/gb3jv<br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Inputs:</strong></span></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Networking:</strong></span></p><br />
<ul><br />
<li>The repeater is curently networked using an unlimited 4G cellular tariff provided by "SMARTY" an H3G company.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Latest News (updated 10/07/2022)</strong></span></p><br />
<p><span style="color: #0000ff;"><strong>Input Recording:</strong></span>&nbsp;In August we are launching a new feature: Repeater recording. Those who have joined the GB3JV web site will be able to access any of these recordings via a link. A great way to review your, and others repeater traffic after the event. See the updated privacy policy at http://www.gb3jv.co.uk/<br />
<p><strong><span style="color: #0000ff;">New Ethernet FWA link:</span>&nbsp;</strong>Justin&rsquo;s been a bit busy installing a new 5GHz link between his house and the GB3JV repeater. The objective of the project is to replace the 4G Cellular internet connection with an RF (Fixed Wireless Access) link back to my house. It&rsquo;s all about the ROI &ndash; &nbsp;4G Cellular @ &pound;18/month: &pound;120 (equipment) + &pound;50 (License) +&pound;10 (cables) = &pound;180 / &pound;18/month = 10 months.</p><br />
<p>The link equipment I&rsquo;ve purchased is the Ubiquiti &ldquo;LiteBeam&rdquo; 5AC Gen2. This equipment is often used for Wireless Broadband connectivity in rural areas and can be configured for point-to-point or point-to-multipoint. The photograph shows the installation on my chimney. The cost of the equipment was just &pound;60 per endpoint, including VAT. Supplier: 4gon.co.uk&nbsp;</p><br />
<p>The equipment provides an ethernet interface at each end and has a comprehensive management system, shown in the attached screen shots. Measured throughput is 30Mb/s the configuration I&rsquo;m using is a 20MHz channel running QAM64 modulation schema (remember&nbsp;this is half duplex!). I&rsquo;ve opted for link resilience over ultimate speed. The unit runs two MIMO (multiple&nbsp;in - multiple out) &nbsp;&ldquo;chains&rdquo; one data stream is horizontally polarised and one vertically polarised. I'm monitoring link performance for a few weeks via my Syslog server instance.</p><br />
<p><strong><span style="color: #0000ff;">Spectrum Planning:</span>&nbsp;</strong>The 5GHz spectrum is divided into three bands:</p><br />
<ul><br />
<li>Band A: 5150-5350 MHz EIRP 200mW&nbsp;alllowed&nbsp;- no fixed outdoor or airborne use, DFS required above 5250 MHz</li><br />
<li>Band B: 5470-5730 MHz 1W EIRP allowed - no airborne use, DFS and TPC required</li><br />
<li>Band C: 5725-5850 MHz 4W EIRP allowed - Must hold a 5.8 GHz licence and all terminals must be registered. DFS and TPC</li><br />
</ul><br />
<p><strong>DFS</strong> =&gt; Dynamic Frequency Selection and <strong>TPC</strong> =&gt; Transmit Power Control</p><br />
<p>Justin's applied to OFCOM for a Band C &ldquo;light licence&rdquo;, but for now he's using Band B. The move to Band C (avoiding the amateur allocations!) will give another 6dB margin due to the higher transmit power and an additional 5dB margin due to the lower noise floor (as measured).<br /><br />Thanks to Gareth G4XAT for his help with antenna erection!</p></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9937GB3JV2022-07-10T21:51:15Z<p>G8YTZ: </p>
<hr />
<div><div><br />
<p><span style="color: #0000ff;"><strong>GB3JV DATV repeater located in Petts Wood, Kent</strong></span></p><br />
</div><br />
<div><br />
<p><strong><span style="color: #0000ff;">Output:</span> 3.404GHz - 2MS/s - DVBS-2 - 0.35 - FEC 4/5 - Horiz. Polarisation</strong></p><br />
</div><br />
<div><br />
<p><strong><span style="color: #0000ff;">Location:&nbsp;</span>JO01AJ (Petts Wood Railway Station)&nbsp;</strong></p><br />
<p><strong><span style="color: #0000ff;">Web Site:</span> <a class="external free" href="http://www.gb3jv.co.uk/" target="_blank" rel="nofollow noreferrer noopener">http://www.gb3jv.co.uk/</a></strong></p><br />
</div><br />
<p><span style="color: #0000ff;"><strong>GB3JV Overview</strong></span></p><br />
<ul><br />
<li>The repeater uses an innovative new controller system based on the Blackmagic ATEM Mini Pro broadcast switcher and Bitfocus&rsquo; &ldquo;Companion&rdquo; middleware</li><br />
<li>The 70cm and 23cm receivers are based on the &ldquo;Minitiouner&rdquo; hardware, developed by F6DZP and the &ldquo;Ryde&rdquo; software developed by members of the BATC</li><br />
<li>When a signal is received a &ldquo;web-hook&rdquo; command is sent to &ldquo;Companion&rdquo; and sends an instruction to the ATEM that instigates a MACRO to transition to the active input</li><br />
<li>The web stream is generated by the ATEM Mini Pro and the media server is based on Guy, M0GUY&rsquo;s PiDeck software</li><br />
<li>You can register on the web site to receive a stream key and to be included in the GB3JV SLACK channel. SLACK will alert you to repeater activity so you can join in with a QSO.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Telemetry:</strong></span></p><br />
<p>The repeater&rsquo;s<span class="Apple-converted-space">&nbsp; </span>telemetry system is based on the &ldquo;Modbus RTU&rdquo; protocol over internet protocol this allows:</p><br />
<ul><br />
<li>Full remote monitoring of the repeater&rsquo;s health with notifications to the keeper&rsquo;s iPhone</li><br />
<li>Full remote control of the repeater&rsquo;s functions and status</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Outputs:</strong></span></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;<strong>&lt;a href="rtmp://rtmp.batc.org.uk/live/gb3jv"&gt;rtmp://rtmp.batc.org.uk/live/gb3jv&lt;/a&gt;</strong></li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Inputs:</strong></span></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Networking:</strong></span></p><br />
<ul><br />
<li>The repeater is curently networked using an unlimited 4G cellular tariff provided by "SMARTY" an H3G company.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Latest News (updated 10/07/2022)</strong></span></p><br />
<p><span style="color: #0000ff;"><strong>Input Recording:</strong></span>&nbsp;In August we are launching a new feature: Repeater recording. Those who have joined the GB3JV web site will be able to access any of these recordings via a link. A great way to review your, and others repeater traffic after the event. See the updated privacy policy at <a class="external free" href="http://www.gb3jv.co.uk/" target="_blank" rel="nofollow noreferrer noopener">http://www.gb3jv.co.uk/</a></p><br />
<p><strong><span style="color: #0000ff;">New Ethernet FWA link:</span>&nbsp;</strong>Justin&rsquo;s been a bit busy installing a new 5GHz link between his house and the GB3JV repeater. The objective of the project is to replace the 4G Cellular internet connection with an RF (Fixed Wireless Access) link back to my house. It&rsquo;s all about the ROI &ndash; &nbsp;4G Cellular @ &pound;18/month: &pound;120 (equipment) + &pound;50 (License) +&pound;10 (cables) = &pound;180 / &pound;18/month = 10 months.</p><br />
<p>The link equipment I&rsquo;ve purchased is the Ubiquiti &ldquo;LiteBeam&rdquo; 5AC Gen2. This equipment is often used for Wireless Broadband connectivity in rural areas and can be configured for point-to-point or point-to-multipoint. The photograph shows the installation on my chimney. The cost of the equipment was just &pound;60 per endpoint, including VAT. Supplier: 4gon.co.uk&nbsp;</p><br />
<p>The equipment provides an ethernet interface at each end and has a comprehensive management system, shown in the attached screen shots. Measured throughput is 30Mb/s the configuration I&rsquo;m using is a 20MHz channel running QAM64 modulation schema (remember&nbsp;this is half duplex!). I&rsquo;ve opted for link resilience over ultimate speed. The unit runs two MIMO (multiple&nbsp;in - multiple out) &nbsp;&ldquo;chains&rdquo; one data stream is horizontally polarised and one vertically polarised. I'm monitoring link performance for a few weeks via my Syslog server instance.</p><br />
<p><strong><span style="color: #0000ff;">Spectrum Planning:</span>&nbsp;</strong>The 5GHz spectrum is divided into three bands:</p><br />
<ul><br />
<li>Band A: 5150-5350 MHz EIRP 200mW&nbsp;alllowed&nbsp;- no fixed outdoor or airborne use, DFS required above 5250 MHz</li><br />
<li>Band B: 5470-5730 MHz 1W EIRP allowed - no airborne use, DFS and TPC required</li><br />
<li>Band C: 5725-5850 MHz 4W EIRP allowed - Must hold a 5.8 GHz licence and all terminals must be registered. DFS and TPC</li><br />
</ul><br />
<p><strong>DFS</strong> =&gt; Dynamic Frequency Selection and <strong>TPC</strong> =&gt; Transmit Power Control</p><br />
<p>Justin's applied to OFCOM for a Band C &ldquo;light licence&rdquo;, but for now he's using Band B. The move to Band C (avoiding the amateur allocations!) will give another 6dB margin due to the higher transmit power and an additional 5dB margin due to the lower noise floor (as measured).<br /><br />Thanks to Gareth G4XAT for his help with antenna erection!</p></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9936GB3JV2022-07-10T21:48:15Z<p>G8YTZ: </p>
<hr />
<div><div><br />
<p><strong>GB3JV DATV repeater located in Petts Wood, Kent</strong></p><br />
</div><br />
<div><br />
<p><strong>Output: 3.404GHz - 2MS/s - DVBS-2 - 0.35 - FEC 4/5 - Horiz. Polarisation</strong></p><br />
</div><br />
<div><br />
<p><strong>Location: &nbsp; &nbsp; JO01AJ (Petts Wood Railway Station)&nbsp;</strong></p><br />
<p><strong>Web Site: http://www.gb3jv.co.uk/<br />
</div><br />
<p><strong>GB3JV Overview</strong></p><br />
<ul><br />
<li>The repeater uses an innovative new controller system based on the Blackmagic ATEM Mini Pro broadcast switcher and Bitfocus&rsquo; &ldquo;Companion&rdquo; middleware</li><br />
<li>The 70cm and 23cm receivers are based on the &ldquo;Minitiouner&rdquo; hardware, developed by F6DZP and the &ldquo;Ryde&rdquo; software developed by members of the BATC</li><br />
<li>When a signal is received a &ldquo;web-hook&rdquo; command is sent to &ldquo;Companion&rdquo; and sends an instruction to the ATEM that instigates a MACRO to transition to the active input</li><br />
<li>The web stream is generated by the ATEM Mini Pro and the media server is based on Guy, M0GUY&rsquo;s PiDeck software</li><br />
<li>You can register on the web site to receive a stream key and to be included in the GB3JV SLACK channel. SLACK will alert you to repeater activity so you can join in with a QSO.</li><br />
</ul><br />
<p><strong>Telemetry:</strong></p><br />
<p>The repeater&rsquo;s<span class="Apple-converted-space">&nbsp; </span>telemetry system is based on the &ldquo;Modbus RTU&rdquo; protocol over internet protocol this allows:</p><br />
<ul><br />
<li>Full remote monitoring of the repeater&rsquo;s health with notifications to the keeper&rsquo;s iPhone</li><br />
<li>Full remote control of the repeater&rsquo;s functions and status</li><br />
</ul><br />
<p><strong>Outputs:</strong></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;<strong><a href="rtmp://rtmp.batc.org.uk/live/gb3jv">rtmp://rtmp.batc.org.uk/live/gb3jv</a></strong></li><br />
</ul><br />
<p><strong>Inputs:</strong></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul><br />
<p><strong>Networking:</strong></p><br />
<ul><br />
<li>The repeater is curently networked using an unlimited 4G cellular tariff provided by "SMARTY" an H3G company.</li><br />
</ul><br />
<p><strong>Latest News (updated 10/07/2022)</strong></p><br />
<p><strong>Input Recording:</strong>&nbsp;In August we are launching a new feature: Repeater recording. Those who have joined the GB3JV web site will be able to access any of these recordings via a link. A great way to review your, and others repeater traffic after the event. See the updated privacy policy at http://www.gb3jv.co.uk/<br />
<p><strong>New Ethernet FWA link:&nbsp;</strong>Justin&rsquo;s been a bit busy installing a new 5GHz link between his house and the GB3JV repeater. The objective of the project is to replace the 4G Cellular internet connection with an RF (Fixed Wireless Access) link back to my house. It&rsquo;s all about the ROI &ndash; &nbsp;4G Cellular @ &pound;18/month: &pound;120 (equipment) + &pound;50 (License) +&pound;10 (cables) = &pound;180 / &pound;18/month = 10 months.</p><br />
<p>The link equipment I&rsquo;ve purchased is the Ubiquiti &ldquo;LiteBeam&rdquo; 5AC Gen2. This equipment is often used for Wireless Broadband connectivity in rural areas and can be configured for point-to-point or point-to-multipoint. The photograph shows the installation on my chimney. The cost of the equipment was just &pound;60 per endpoint, including VAT. Supplier: 4gon.co.uk&nbsp;</p><br />
<p>The equipment provides an ethernet interface at each end and has a comprehensive management system, shown in the attached screen shots. Measured throughput is 30Mb/s the configuration I&rsquo;m using is a 20MHz channel running QAM64 modulation schema (remember&nbsp;this is half duplex!). I&rsquo;ve opted for link resilience over ultimate speed. The unit runs two MIMO (multiple&nbsp;in - multiple out) &nbsp;&ldquo;chains&rdquo; one data stream is horizontally polarised and one vertically polarised. I'm monitoring link performance for a few weeks via my Syslog server instance.</p><br />
<p><strong>Spectrum Planning:&nbsp;</strong>The 5GHz spectrum is divided into three bands:</p><br />
<ul><br />
<li>Band A: 5150-5350 MHz EIRP 200mW&nbsp;alllowed&nbsp;- no fixed outdoor or airborne use, DFS required above 5250 MHz</li><br />
<li>Band B: 5470-5730 MHz 1W EIRP allowed - no airborne use, DFS and TPC required</li><br />
<li>Band C: 5725-5850 MHz 4W EIRP allowed - Must hold a 5.8 GHz licence and all terminals must be registered. DFS and TPC</li><br />
</ul><br />
<p><strong>DFS</strong> =&gt; Dynamic Frequency Selection and <strong>TPC</strong> =&gt; Transmit Power Control</p><br />
<p>Justin's applied to OFCOM for a Band C &ldquo;light licence&rdquo;, but for now he's using Band B. The move to Band C (avoiding the amateur allocations!) will give another 6dB margin due to the higher transmit power and an additional 5dB margin due to the lower noise floor (as measured).<br /><br />Thanks to Gareth G4XAT for his help with antenna erection!</p></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9935GB3JV2022-07-10T21:46:02Z<p>G8YTZ: </p>
<hr />
<div><div><br />
<p><strong>GB3JV DATV repeater located in Petts Wood, Kent</strong></p><br />
</div><br />
<div><br />
<p><strong>Output: 3.404GHz - 2MS/s - DVBS-2 - 0.35 - FEC 4/5 - Horiz. Polarisation</strong></p><br />
</div><br />
<div><br />
<p><strong>Location: &nbsp; &nbsp; JO01AJ (Petts Wood Railway Station)&nbsp;</strong></p><br />
<p><strong>Web Site: &nbsp;&nbsp;&nbsp;<span style="color: #0000ff;"><a class="external free" style="color: #0000ff;" href="http://www.gb3jv.co.uk/" target="_blank" rel="nofollow noreferrer noopener">http://www.gb3jv.co.uk/</a></span></strong></p><br />
</div><br />
<p><strong>GB3JV Overview</strong></p><br />
<ul><br />
<li>The repeater uses an innovative new controller system based on the Blackmagic ATEM Mini Pro broadcast switcher and Bitfocus&rsquo; &ldquo;Companion&rdquo; middleware</li><br />
<li>The 70cm and 23cm receivers are based on the &ldquo;Minitiouner&rdquo; hardware, developed by F6DZP and the &ldquo;Ryde&rdquo; software developed by members of the BATC</li><br />
<li>When a signal is received a &ldquo;web-hook&rdquo; command is sent to &ldquo;Companion&rdquo; and sends an instruction to the ATEM that instigates a MACRO to transition to the active input</li><br />
<li>The web stream is generated by the ATEM Mini Pro and the media server is based on Guy, M0GUY&rsquo;s PiDeck software</li><br />
<li>You can register on the web site to receive a stream key and to be included in the GB3JV SLACK channel. SLACK will alert you to repeater activity so you can join in with a QSO.</li><br />
</ul><br />
<p><strong>Telemetry:</strong></p><br />
<p>The repeater&rsquo;s<span class="Apple-converted-space">&nbsp; </span>telemetry system is based on the &ldquo;Modbus RTU&rdquo; protocol over internet protocol this allows:</p><br />
<ul><br />
<li>Full remote monitoring of the repeater&rsquo;s health with notifications to the keeper&rsquo;s iPhone</li><br />
<li>Full remote control of the repeater&rsquo;s functions and status</li><br />
</ul><br />
<p><strong>Outputs:</strong></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;<strong><a href="rtmp://rtmp.batc.org.uk/live/gb3jv">rtmp://rtmp.batc.org.uk/live/gb3jv</a></strong></li><br />
</ul><br />
<p><strong>Inputs:</strong></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul><br />
<p><strong>Networking:</strong></p><br />
<ul><br />
<li>The repeater is curently networked using an unlimited 4G cellular tariff provided by "SMARTY" an H3G company.</li><br />
</ul><br />
<p><strong>Latest News (updated 10/07/2022)</strong></p><br />
<p><strong>Input Recording:</strong>&nbsp;In August we are launching a new feature: Repeater recording. Those who have joined the GB3JV web site will be able to access any of these recordings via a link. A great way to review your, and others repeater traffic after the event. See the updated privacy policy at&nbsp;<span style="color: #0000ff;"><strong><a class="external free" style="color: #0000ff;" href="http://www.gb3jv.co.uk/" target="_blank" rel="nofollow noreferrer noopener">http://www.gb3jv.co.uk</a></strong></span></p><br />
<p><strong>New Ethernet FWA link:&nbsp;</strong>Justin&rsquo;s been a bit busy installing a new 5GHz link between his house and the GB3JV repeater. The objective of the project is to replace the 4G Cellular internet connection with an RF (Fixed Wireless Access) link back to my house. It&rsquo;s all about the ROI &ndash; &nbsp;4G Cellular @ &pound;18/month: &pound;120 (equipment) + &pound;50 (License) +&pound;10 (cables) = &pound;180 / &pound;18/month = 10 months.</p><br />
<p>The link equipment I&rsquo;ve purchased is the Ubiquiti &ldquo;LiteBeam&rdquo; 5AC Gen2. This equipment is often used for Wireless Broadband connectivity in rural areas and can be configured for point-to-point or point-to-multipoint. The photograph shows the installation on my chimney. The cost of the equipment was just &pound;60 per endpoint, including VAT. Supplier: 4gon.co.uk&nbsp;</p><br />
<p>The equipment provides an ethernet interface at each end and has a comprehensive management system, shown in the attached screen shots. Measured throughput is 30Mb/s the configuration I&rsquo;m using is a 20MHz channel running QAM64 modulation schema (remember&nbsp;this is half duplex!). I&rsquo;ve opted for link resilience over ultimate speed. The unit runs two MIMO (multiple&nbsp;in - multiple out) &nbsp;&ldquo;chains&rdquo; one data stream is horizontally polarised and one vertically polarised. I'm monitoring link performance for a few weeks via my Syslog server instance.</p><br />
<p><strong>Spectrum Planning:&nbsp;</strong>The 5GHz spectrum is divided into three bands:</p><br />
<ul><br />
<li>Band A: 5150-5350 MHz EIRP 200mW&nbsp;alllowed&nbsp;- no fixed outdoor or airborne use, DFS required above 5250 MHz</li><br />
<li>Band B: 5470-5730 MHz 1W EIRP allowed - no airborne use, DFS and TPC required</li><br />
<li>Band C: 5725-5850 MHz 4W EIRP allowed - Must hold a 5.8 GHz licence and all terminals must be registered. DFS and TPC</li><br />
</ul><br />
<p><strong>DFS</strong> =&gt; Dynamic Frequency Selection and <strong>TPC</strong> =&gt; Transmit Power Control</p><br />
<p>Justin's applied to OFCOM for a Band C &ldquo;light licence&rdquo;, but for now he's using Band B. The move to Band C (avoiding the amateur allocations!) will give another 6dB margin due to the higher transmit power and an additional 5dB margin due to the lower noise floor (as measured).<br /><br />Thanks to Gareth G4XAT for his help with antenna erection!</p></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9934GB3JV2022-07-10T21:41:41Z<p>G8YTZ: </p>
<hr />
<div><div><br />
<p><strong>GB3JV DATV repeater located in Petts Wood, Kent</strong></p><br />
</div><br />
<div><br />
<p><strong>Output: 3.404GHz - 2MS/s - DVBS-2 - 0.35 - FEC 4/5 - Horiz. Polarisation</strong></p><br />
</div><br />
<div><br />
<p><strong>Location: &nbsp; &nbsp; JO01AJ (Petts Wood Railway Station)&nbsp;</strong></p><br />
<p><strong>Web Site: &nbsp;&nbsp;&nbsp;http://www.gb3jv.co.uk/<br />
</div><br />
<p><span style="color: #0000ff;"><strong>GB3JV Overview</strong></span></p><br />
<ul><br />
<li>The repeater uses an innovative new controller system based on the Blackmagic ATEM Mini Pro broadcast switcher and Bitfocus&rsquo; &ldquo;Companion&rdquo; middleware</li><br />
<li>The 70cm and 23cm receivers are based on the &ldquo;Minitiouner&rdquo; hardware, developed by F6DZP and the &ldquo;Ryde&rdquo; software developed by members of the BATC</li><br />
<li>When a signal is received a &ldquo;web-hook&rdquo; command is sent to &ldquo;Companion&rdquo; and sends an instruction to the ATEM that instigates a MACRO to transition to the active input</li><br />
<li>The web stream is generated by the ATEM Mini Pro and the media server is based on Guy, M0GUY&rsquo;s PiDeck software</li><br />
<li>You can register on the web site to receive a stream key and to be included in the GB3JV SLACK channel. SLACK will alert you to repeater activity so you can join in with a QSO.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Telemetry:</strong></span></p><br />
<p>The repeater&rsquo;s<span class="Apple-converted-space">&nbsp; </span>telemetry system is based on the &ldquo;Modbus RTU&rdquo; protocol over internet protocol this allows:</p><br />
<ul><br />
<li>Full remote monitoring of the repeater&rsquo;s health with notifications to the keeper&rsquo;s iPhone</li><br />
<li>Full remote control of the repeater&rsquo;s functions and status<span class="Apple-converted-space">&nbsp;</span></li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Outputs:</strong></span></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;rtmp://rtmp.batc.org.uk/live/gb3jv</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Inputs:</strong></span></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Networking:</strong></span></p><br />
<ul><br />
<li>The repeater is curently networked using an unlimited 4G cellular tariff provided by "SMARTY" an H3G company.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Latest News (updated 10/07/2022)</strong></span></p><br />
<p><strong>Input Recording:</strong>&nbsp;In August we are launching a new feature: Repeater recording. Those who have joined the GB3JV web site will be able to access any of these recordings via a link. A great way to review your, and others repeater traffic after the event. See the updated privacy policy at&nbsp;<strong>http://www.gb3jv.co.uk<br />
<p style="font-weight: 400;"><span style="color: #0000ff;"><strong><span style="color: #000000;">New Ethernet FWA link:</span>&nbsp;</strong></span>Justin&rsquo;s been a bit busy installing a new 5GHz link between his house and the GB3JV repeater. The objective of the project is to replace the 4G Cellular internet connection with an RF (Fixed Wireless Access) link back to my house. It&rsquo;s all about the ROI &ndash; &nbsp;4G Cellular @ &pound;18/month: &pound;120 (equipment) + &pound;50 (License) +&pound;10 (cables) = &pound;180 / &pound;18/month = 10 months.</p><br />
<p style="font-weight: 400;">The link equipment I&rsquo;ve purchased is the Ubiquiti &ldquo;LiteBeam&rdquo; 5AC Gen2. This equipment is often used for Wireless Broadband connectivity in rural areas and can be configured for point-to-point or point-to-multipoint. The photograph shows the installation on my chimney. The cost of the equipment was just &pound;60 per endpoint, including VAT. Supplier: 4gon.co.uk&nbsp;</p><br />
<p style="font-weight: 400;">The equipment provides an ethernet interface at each end and has a comprehensive management system, shown in the attached screen shots. Measured throughput is 30Mb/s the configuration I&rsquo;m using is a 20MHz channel running QAM64 modulation schema (remember&nbsp;this is half duplex!). I&rsquo;ve opted for link resilience over ultimate speed. The unit runs two MIMO (multiple&nbsp;in - multiple out) &nbsp;&ldquo;chains&rdquo; one data stream is horizontally polarised and one vertically polarised. I'm monitoring link performance for a few weeks via my Syslog server instance.</p><br />
<p style="font-weight: 400;"><strong>Spectrum Planning:&nbsp;</strong>The 5GHz spectrum is divided into three bands:</p><br />
<ul style="font-weight: 400;"><br />
<li>Band A: 5150-5350 MHz EIRP 200mW&nbsp;alllowed&nbsp;- no fixed outdoor or airborne use, DFS required above 5250 MHz</li><br />
<li>Band B: 5470-5730 MHz 1W EIRP allowed - no airborne use, DFS and TPC required</li><br />
<li>Band C: 5725-5850 MHz 4W EIRP allowed - Must hold a 5.8 GHz licence and all terminals must be registered. DFS and TPC</li><br />
</ul><br />
<p style="font-weight: 400;"><strong>DFS</strong> =&gt; Dynamic Frequency Selection and <strong>TPC</strong> =&gt; Transmit Power Control</p><br />
<p style="font-weight: 400;">Justin's applied to OFCOM for a Band C &ldquo;light licence&rdquo;, but for now he's using Band B. The move to Band C (avoiding the amateur allocations!) will give another 6dB margin due to the higher transmit power and an additional 5dB margin due to the lower noise floor (as measured).<br /><br />Thanks to Gareth G4XAT for his help with antenna erection!<br /><br /></p></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9933GB3JV2022-07-10T21:40:41Z<p>G8YTZ: </p>
<hr />
<div><div><br />
<p><strong>GB3JV DATV repeater located in Petts Wood, Kent</strong></p><br />
</div><br />
<div><br />
<p><strong>Output: 3.404GHz - 2MS/s - DVBS-2 - 0.35 - FEC 4/5 - Horiz. Polarisation</strong></p><br />
</div><br />
<div><br />
<p><strong>Location: &nbsp; &nbsp; JO01AJ (Petts Wood Railway Station)&nbsp;</strong></p><br />
<p><strong>Web Site: &nbsp;&nbsp;&nbsp; http://www.gb3jv.co.uk/<br />
</div><br />
<p><span style="color: #0000ff;"><strong>GB3JV Overview</strong></span></p><br />
<ul><br />
<li>The repeater uses an innovative new controller system based on the Blackmagic ATEM Mini Pro broadcast switcher and Bitfocus&rsquo; &ldquo;Companion&rdquo; middleware</li><br />
<li>The 70cm and 23cm receivers are based on the &ldquo;Minitiouner&rdquo; hardware, developed by F6DZP and the &ldquo;Ryde&rdquo; software developed by members of the BATC</li><br />
<li>When a signal is received a &ldquo;web-hook&rdquo; command is sent to &ldquo;Companion&rdquo; and sends an instruction to the ATEM that instigates a MACRO to transition to the active input</li><br />
<li>The web stream is generated by the ATEM Mini Pro and the media server is based on Guy, M0GUY&rsquo;s PiDeck software</li><br />
<li>You can register on the web site to receive a stream key and to be included in the GB3JV SLACK channel. SLACK will alert you to repeater activity so you can join in with a QSO.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Telemetry:</strong></span></p><br />
<p>The repeater&rsquo;s<span class="Apple-converted-space">&nbsp; </span>telemetry system is based on the &ldquo;Modbus RTU&rdquo; protocol over internet protocol this allows:</p><br />
<ul><br />
<li>Full remote monitoring of the repeater&rsquo;s health with notifications to the keeper&rsquo;s iPhone</li><br />
<li>Full remote control of the repeater&rsquo;s functions and status<span class="Apple-converted-space">&nbsp;</span></li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Outputs:</strong></span></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;rtmp://rtmp.batc.org.uk/live/gb3jv</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Inputs:</strong></span></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Networking:</strong></span></p><br />
<ul><br />
<li>The repeater is curently networked using an unlimited 4G cellular tariff provided by "SMARTY" an H3G company.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Latest News (updated 10/07/2022)</strong></span></p><br />
<p><strong>Input Recording:</strong>&nbsp;In August we are launching a new feature: Repeater recording. Those who have joined the GB3JV web site will be able to access any of these recordings via a link. A great way to review your, and others repeater traffic after the event. See the updated privacy policy at&nbsp;<strong>http://www.gb3jv.co.uk<br />
<p style="font-weight: 400;"><span style="color: #0000ff;"><strong><span style="color: #000000;">New Ethernet FWA link:</span>&nbsp;</strong></span>Justin&rsquo;s been a bit busy installing a new 5GHz link between his house and the GB3JV repeater. The objective of the project is to replace the 4G Cellular internet connection with an RF (Fixed Wireless Access) link back to my house. It&rsquo;s all about the ROI &ndash; &nbsp;4G Cellular @ &pound;18/month: &pound;120 (equipment) + &pound;50 (License) +&pound;10 (cables) = &pound;180 / &pound;18/month = 10 months.</p><br />
<p style="font-weight: 400;">The link equipment I&rsquo;ve purchased is the Ubiquiti &ldquo;LiteBeam&rdquo; 5AC Gen2. This equipment is often used for Wireless Broadband connectivity in rural areas and can be configured for point-to-point or point-to-multipoint. The photograph shows the installation on my chimney. The cost of the equipment was just &pound;60 per endpoint, including VAT. Supplier: 4gon.co.uk&nbsp;</p><br />
<p style="font-weight: 400;">The equipment provides an ethernet interface at each end and has a comprehensive management system, shown in the attached screen shots. Measured throughput is 30Mb/s the configuration I&rsquo;m using is a 20MHz channel running QAM64 modulation schema (remember&nbsp;this is half duplex!). I&rsquo;ve opted for link resilience over ultimate speed. The unit runs two MIMO (multiple&nbsp;in - multiple out) &nbsp;&ldquo;chains&rdquo; one data stream is horizontally polarised and one vertically polarised. I'm monitoring link performance for a few weeks via my Syslog server instance.</p><br />
<p style="font-weight: 400;"><strong>Spectrum Planning:&nbsp;</strong>The 5GHz spectrum is divided into three bands:</p><br />
<ul style="font-weight: 400;"><br />
<li>Band A: 5150-5350 MHz EIRP 200mW&nbsp;alllowed&nbsp;- no fixed outdoor or airborne use, DFS required above 5250 MHz</li><br />
<li>Band B: 5470-5730 MHz 1W EIRP allowed - no airborne use, DFS and TPC required</li><br />
<li>Band C: 5725-5850 MHz 4W EIRP allowed - Must hold a 5.8 GHz licence and all terminals must be registered. DFS and TPC</li><br />
</ul><br />
<p style="font-weight: 400;"><strong>DFS</strong> =&gt; Dynamic Frequency Selection and <strong>TPC</strong> =&gt; Transmit Power Control</p><br />
<p style="font-weight: 400;">Justin's applied to OFCOM for a Band C &ldquo;light licence&rdquo;, but for now he's using Band B. The move to Band C (avoiding the amateur allocations!) will give another 6dB margin due to the higher transmit power and an additional 5dB margin due to the lower noise floor (as measured).<br /><br />Thanks to Gareth G4XAT for his help with antenna erection!<br /><br /></p></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9932GB3JV2022-07-10T21:40:01Z<p>G8YTZ: </p>
<hr />
<div><div><br />
<p><strong>GB3JV DATV repeater located in Petts Wood, Kent</strong></p><br />
</div><br />
<div><br />
<p><strong>Output: 3.404GHz - 2MS/s - DVBS-2 - 0.35 - FEC 4/5 - Horiz. Polarisation</strong></p><br />
</div><br />
<div><br />
<p><strong>Location: &nbsp; &nbsp; JO01AJ (Petts Wood Railway Station)&nbsp;</strong></p><br />
<p><strong>Web Site: &nbsp;&nbsp;&nbsp; http://www.gb3jv.co.uk/<br />
</div><br />
<p><span style="color: #0000ff;"><strong>GB3JV Overview</strong></span></p><br />
<ul><br />
<li>The repeater uses an innovative new controller system based on the Blackmagic ATEM Mini Pro broadcast switcher and Bitfocus&rsquo; &ldquo;Companion&rdquo; middleware</li><br />
<li>The 70cm and 23cm receivers are based on the &ldquo;Minitiouner&rdquo; hardware, developed by F6DZP and the &ldquo;Ryde&rdquo; software developed by members of the BATC</li><br />
<li>When a signal is received a &ldquo;web-hook&rdquo; command is sent to &ldquo;Companion&rdquo; and sends an instruction to the ATEM that instigates a MACRO to transition to the active input</li><br />
<li>The web stream is generated by the ATEM Mini Pro and the media server is based on Guy, M0GUY&rsquo;s PiDeck software</li><br />
<li>You can register on the web site to receive a stream key and to be included in the GB3JV SLACK channel. SLACK will alert you to repeater activity so you can join in with a QSO.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Telemetry:</strong></span></p><br />
<p>The repeater&rsquo;s<span class="Apple-converted-space">&nbsp; </span>telemetry system is based on the &ldquo;Modbus RTU&rdquo; protocol over internet protocol this allows:</p><br />
<ul><br />
<li>Full remote monitoring of the repeater&rsquo;s health with notifications to the keeper&rsquo;s iPhone</li><br />
<li>Full remote control of the repeater&rsquo;s functions and status<span class="Apple-converted-space">&nbsp;</span></li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Outputs:</strong></span></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;rtmp://rtmp.batc.org.uk/live/gb3jv</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Inputs:</strong></span></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Networking:</strong></span></p><br />
<ul><br />
<li>The repeater is curently networked using an unlimited 4G cellular tariff provided by "SMARTY" an H3G company.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Latest News (updated 10/07/2022)</strong></span></p><br />
<p><strong>Input Recording:</strong>&nbsp;In August we are launching a new feature: Repeater recording. Those who have joined the GB3JV web site will be able to access any of these recordings via a link. A great way to review your, and others repeater traffic after the event. See the updated privacy policy at&nbsp;<strong>http://www.gb3jv.co.uk/</a></strong></p><br />
<p style="font-weight: 400;"><span style="color: #0000ff;"><strong><span style="color: #000000;">New Ethernet FWA link:</span>&nbsp;</strong></span>Justin&rsquo;s been a bit busy installing a new 5GHz link between his house and the GB3JV repeater. The objective of the project is to replace the 4G Cellular internet connection with an RF (Fixed Wireless Access) link back to my house. It&rsquo;s all about the ROI &ndash; &nbsp;4G Cellular @ &pound;18/month: &pound;120 (equipment) + &pound;50 (License) +&pound;10 (cables) = &pound;180 / &pound;18/month = 10 months.</p><br />
<p style="font-weight: 400;">The link equipment I&rsquo;ve purchased is the Ubiquiti &ldquo;LiteBeam&rdquo; 5AC Gen2. This equipment is often used for Wireless Broadband connectivity in rural areas and can be configured for point-to-point or point-to-multipoint. The photograph shows the installation on my chimney. The cost of the equipment was just &pound;60 per endpoint, including VAT. Supplier: 4gon.co.uk&nbsp;</p><br />
<p style="font-weight: 400;">The equipment provides an ethernet interface at each end and has a comprehensive management system, shown in the attached screen shots. Measured throughput is 30Mb/s the configuration I&rsquo;m using is a 20MHz channel running QAM64 modulation schema (remember&nbsp;this is half duplex!). I&rsquo;ve opted for link resilience over ultimate speed. The unit runs two MIMO (multiple&nbsp;in - multiple out) &nbsp;&ldquo;chains&rdquo; one data stream is horizontally polarised and one vertically polarised. I'm monitoring link performance for a few weeks via my Syslog server instance.</p><br />
<p style="font-weight: 400;"><strong>Spectrum Planning:&nbsp;</strong>The 5GHz spectrum is divided into three bands:</p><br />
<ul style="font-weight: 400;"><br />
<li>Band A: 5150-5350 MHz EIRP 200mW&nbsp;alllowed&nbsp;- no fixed outdoor or airborne use, DFS required above 5250 MHz</li><br />
<li>Band B: 5470-5730 MHz 1W EIRP allowed - no airborne use, DFS and TPC required</li><br />
<li>Band C: 5725-5850 MHz 4W EIRP allowed - Must hold a 5.8 GHz licence and all terminals must be registered. DFS and TPC</li><br />
</ul><br />
<p style="font-weight: 400;"><strong>DFS</strong> =&gt; Dynamic Frequency Selection and <strong>TPC</strong> =&gt; Transmit Power Control</p><br />
<p style="font-weight: 400;">Justin's applied to OFCOM for a Band C &ldquo;light licence&rdquo;, but for now he's using Band B. The move to Band C (avoiding the amateur allocations!) will give another 6dB margin due to the higher transmit power and an additional 5dB margin due to the lower noise floor (as measured).<br /><br />Thanks to Gareth G4XAT for his help with antenna erection!<br /><br /></p></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9931GB3JV2022-07-10T21:39:05Z<p>G8YTZ: </p>
<hr />
<div><div><br />
<p><strong>GB3JV DATV repeater located in Petts Wood, Kent</strong></p><br />
</div><br />
<div><br />
<p><strong>Output: 3.404GHz - 2MS/s - DVBS-2 - 0.35 - FEC 4/5 - Horiz. Polarisation</strong></p><br />
</div><br />
<div><br />
<p><strong>Location: &nbsp; &nbsp; JO01AJ (Petts Wood Railway Station)&nbsp;</strong></p><br />
<p><strong>Web Site: &nbsp;&nbsp;&nbsp; http://www.gb3jv.co.uk/<br />
</div><br />
<p><span style="color: #0000ff;"><strong>GB3JV Overview</strong></span></p><br />
<ul><br />
<li>The repeater uses an innovative new controller system based on the Blackmagic ATEM Mini Pro broadcast switcher and Bitfocus&rsquo; &ldquo;Companion&rdquo; middleware</li><br />
<li>The 70cm and 23cm receivers are based on the &ldquo;Minitiouner&rdquo; hardware, developed by F6DZP and the &ldquo;Ryde&rdquo; software developed by members of the BATC</li><br />
<li>When a signal is received a &ldquo;web-hook&rdquo; command is sent to &ldquo;Companion&rdquo; and sends an instruction to the ATEM that instigates a MACRO to transition to the active input</li><br />
<li>The web stream is generated by the ATEM Mini Pro and the media server is based on Guy, M0GUY&rsquo;s PiDeck software</li><br />
<li>You can register on the web site to receive a stream key and to be included in the GB3JV SLACK channel. SLACK will alert you to repeater activity so you can join in with a QSO.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Telemetry:</strong></span></p><br />
<p>The repeater&rsquo;s<span class="Apple-converted-space">&nbsp; </span>telemetry system is based on the &ldquo;Modbus RTU&rdquo; protocol over internet protocol this allows:</p><br />
<ul><br />
<li>Full remote monitoring of the repeater&rsquo;s health with notifications to the keeper&rsquo;s iPhone</li><br />
<li>Full remote control of the repeater&rsquo;s functions and status<span class="Apple-converted-space">&nbsp;</span></li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Outputs:</strong></span></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;rtmp://rtmp.batc.org.uk/live/gb3jv</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Inputs:</strong></span></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Networking:</strong></span></p><br />
<ul><br />
<li>The repeater is curently networked using an unlimited 4G cellular tariff provided by "SMARTY" an H3G company.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Latest News (updated 10/07/2022)</strong></span></p><br />
<p><strong>Input Recording:</strong>&nbsp;In August we are launching a new feature: Repeater recording. Those who have joined the GB3JV web site will be able to access any of these recordings via a link. A great way to review your, and others repeater traffic after the event. See the updated privacy policy at&nbsp;<strong><a href="http://www.gb3jv.co.uk/">www.gb3jv.co.uk</a></strong></p><br />
<p style="font-weight: 400;"><span style="color: #0000ff;"><strong><span style="color: #000000;">New Ethernet FWA link:</span>&nbsp;</strong></span>Justin&rsquo;s been a bit busy installing a new 5GHz link between his house and the GB3JV repeater. The objective of the project is to replace the 4G Cellular internet connection with an RF (Fixed Wireless Access) link back to my house. It&rsquo;s all about the ROI &ndash; &nbsp;4G Cellular @ &pound;18/month: &pound;120 (equipment) + &pound;50 (License) +&pound;10 (cables) = &pound;180 / &pound;18/month = 10 months.</p><br />
<p style="font-weight: 400;">The link equipment I&rsquo;ve purchased is the Ubiquiti &ldquo;LiteBeam&rdquo; 5AC Gen2. This equipment is often used for Wireless Broadband connectivity in rural areas and can be configured for point-to-point or point-to-multipoint. The photograph shows the installation on my chimney. The cost of the equipment was just &pound;60 per endpoint, including VAT. Supplier: 4gon.co.uk&nbsp;</p><br />
<p style="font-weight: 400;">The equipment provides an ethernet interface at each end and has a comprehensive management system, shown in the attached screen shots. Measured throughput is 30Mb/s the configuration I&rsquo;m using is a 20MHz channel running QAM64 modulation schema (remember&nbsp;this is half duplex!). I&rsquo;ve opted for link resilience over ultimate speed. The unit runs two MIMO (multiple&nbsp;in - multiple out) &nbsp;&ldquo;chains&rdquo; one data stream is horizontally polarised and one vertically polarised. I'm monitoring link performance for a few weeks via my Syslog server instance.</p><br />
<p style="font-weight: 400;"><strong>Spectrum Planning:&nbsp;</strong>The 5GHz spectrum is divided into three bands:</p><br />
<ul style="font-weight: 400;"><br />
<li>Band A: 5150-5350 MHz EIRP 200mW&nbsp;alllowed&nbsp;- no fixed outdoor or airborne use, DFS required above 5250 MHz</li><br />
<li>Band B: 5470-5730 MHz 1W EIRP allowed - no airborne use, DFS and TPC required</li><br />
<li>Band C: 5725-5850 MHz 4W EIRP allowed - Must hold a 5.8 GHz licence and all terminals must be registered. DFS and TPC</li><br />
</ul><br />
<p style="font-weight: 400;"><strong>DFS</strong> =&gt; Dynamic Frequency Selection and <strong>TPC</strong> =&gt; Transmit Power Control</p><br />
<p style="font-weight: 400;">Justin's applied to OFCOM for a Band C &ldquo;light licence&rdquo;, but for now he's using Band B. The move to Band C (avoiding the amateur allocations!) will give another 6dB margin due to the higher transmit power and an additional 5dB margin due to the lower noise floor (as measured).<br /><br />Thanks to Gareth G4XAT for his help with antenna erection!<br /><br /></p></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9930GB3JV2022-07-10T21:37:35Z<p>G8YTZ: </p>
<hr />
<div><div><br />
<p><strong>GB3JV DATV repeater located in Petts Wood, Kent</strong></p><br />
</div><br />
<div><br />
<p><strong>Output: 3.404GHz - 2MS/s - DVBS-2 - 0.35 - FEC 4/5 - Horiz. Polarisation</strong></p><br />
</div><br />
<div><br />
<p><strong>Location: &nbsp; &nbsp; JO01AJ (Petts Wood Railway Station)&nbsp;</strong></p><br />
<p><strong>Web Site: &nbsp;&nbsp;&nbsp;<a href="http://www.gb3jv.co.uk/">www.gb3jv.co.uk</a></strong></p><br />
</div><br />
<p><span style="color: #0000ff;"><strong>GB3JV Overview</strong></span></p><br />
<ul><br />
<li>The repeater uses an innovative new controller system based on the Blackmagic ATEM Mini Pro broadcast switcher and Bitfocus&rsquo; &ldquo;Companion&rdquo; middleware</li><br />
<li>The 70cm and 23cm receivers are based on the &ldquo;Minitiouner&rdquo; hardware, developed by F6DZP and the &ldquo;Ryde&rdquo; software developed by members of the BATC</li><br />
<li>When a signal is received a &ldquo;web-hook&rdquo; command is sent to &ldquo;Companion&rdquo; and sends an instruction to the ATEM that instigates a MACRO to transition to the active input</li><br />
<li>The web stream is generated by the ATEM Mini Pro and the media server is based on Guy, M0GUY&rsquo;s PiDeck software</li><br />
<li>You can register on the web site to receive a stream key and to be included in the GB3JV SLACK channel. SLACK will alert you to repeater activity so you can join in with a QSO.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Telemetry:</strong></span></p><br />
<p>The repeater&rsquo;s<span class="Apple-converted-space">&nbsp; </span>telemetry system is based on the &ldquo;Modbus RTU&rdquo; protocol over internet protocol this allows:</p><br />
<ul><br />
<li>Full remote monitoring of the repeater&rsquo;s health with notifications to the keeper&rsquo;s iPhone</li><br />
<li>Full remote control of the repeater&rsquo;s functions and status<span class="Apple-converted-space">&nbsp;</span></li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Outputs:</strong></span></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;rtmp://rtmp.batc.org.uk/live/gb3jv</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Inputs:</strong></span></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Networking:</strong></span></p><br />
<ul><br />
<li>The repeater is curently networked using an unlimited 4G cellular tariff provided by "SMARTY" an H3G company.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Latest News (updated 10/07/2022)</strong></span></p><br />
<p><strong>Input Recording:</strong>&nbsp;In August we are launching a new feature: Repeater recording. Those who have joined the GB3JV web site will be able to access any of these recordings via a link. A great way to review your, and others repeater traffic after the event. See the updated privacy policy at&nbsp;<strong><a href="http://www.gb3jv.co.uk/">www.gb3jv.co.uk</a></strong></p><br />
<p style="font-weight: 400;"><span style="color: #0000ff;"><strong><span style="color: #000000;">New Ethernet FWA link:</span>&nbsp;</strong></span>Justin&rsquo;s been a bit busy installing a new 5GHz link between his house and the GB3JV repeater. The objective of the project is to replace the 4G Cellular internet connection with an RF (Fixed Wireless Access) link back to my house. It&rsquo;s all about the ROI &ndash; &nbsp;4G Cellular @ &pound;18/month: &pound;120 (equipment) + &pound;50 (License) +&pound;10 (cables) = &pound;180 / &pound;18/month = 10 months.</p><br />
<p style="font-weight: 400;">The link equipment I&rsquo;ve purchased is the Ubiquiti &ldquo;LiteBeam&rdquo; 5AC Gen2. This equipment is often used for Wireless Broadband connectivity in rural areas and can be configured for point-to-point or point-to-multipoint. The photograph shows the installation on my chimney. The cost of the equipment was just &pound;60 per endpoint, including VAT. Supplier: 4gon.co.uk&nbsp;</p><br />
<p style="font-weight: 400;">The equipment provides an ethernet interface at each end and has a comprehensive management system, shown in the attached screen shots. Measured throughput is 30Mb/s the configuration I&rsquo;m using is a 20MHz channel running QAM64 modulation schema (remember&nbsp;this is half duplex!). I&rsquo;ve opted for link resilience over ultimate speed. The unit runs two MIMO (multiple&nbsp;in - multiple out) &nbsp;&ldquo;chains&rdquo; one data stream is horizontally polarised and one vertically polarised. I'm monitoring link performance for a few weeks via my Syslog server instance.</p><br />
<p style="font-weight: 400;"><strong>Spectrum Planning:&nbsp;</strong>The 5GHz spectrum is divided into three bands:</p><br />
<ul style="font-weight: 400;"><br />
<li>Band A: 5150-5350 MHz EIRP 200mW&nbsp;alllowed&nbsp;- no fixed outdoor or airborne use, DFS required above 5250 MHz</li><br />
<li>Band B: 5470-5730 MHz 1W EIRP allowed - no airborne use, DFS and TPC required</li><br />
<li>Band C: 5725-5850 MHz 4W EIRP allowed - Must hold a 5.8 GHz licence and all terminals must be registered. DFS and TPC</li><br />
</ul><br />
<p style="font-weight: 400;"><strong>DFS</strong> =&gt; Dynamic Frequency Selection and <strong>TPC</strong> =&gt; Transmit Power Control</p><br />
<p style="font-weight: 400;">Justin's applied to OFCOM for a Band C &ldquo;light licence&rdquo;, but for now he's using Band B. The move to Band C (avoiding the amateur allocations!) will give another 6dB margin due to the higher transmit power and an additional 5dB margin due to the lower noise floor (as measured).<br /><br />Thanks to Gareth G4XAT for his help with antenna erection!<br /><br /></p></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9929GB3JV2022-07-10T21:36:39Z<p>G8YTZ: </p>
<hr />
<div><div><br />
<p><strong>GB3JV DATV repeater located in Petts Wood, Kent</strong></p><br />
</div><br />
<div><br />
<p><strong>Output: 3.404GHz - 2MS/s - DVBS-2 - 0.35 - FEC 4/5 - Horiz. Polarisation</strong></p><br />
</div><br />
<div><br />
<p><strong>Location: &nbsp; &nbsp; JO01AJ (Petts Wood Railway Station)&nbsp;</strong></p><br />
<p><strong>Web Site: #0000ff;"><strong>www.gb3jv.co.uk</strong></span></p><br />
</div><br />
<p><span style="color: #0000ff;"><strong>GB3JV Overview</strong></span></p><br />
<ul><br />
<li>The repeater uses an innovative new controller system based on the Blackmagic ATEM Mini Pro broadcast switcher and Bitfocus&rsquo; &ldquo;Companion&rdquo; middleware</li><br />
<li>The 70cm and 23cm receivers are based on the &ldquo;Minitiouner&rdquo; hardware, developed by F6DZP and the &ldquo;Ryde&rdquo; software developed by members of the BATC</li><br />
<li>When a signal is received a &ldquo;web-hook&rdquo; command is sent to &ldquo;Companion&rdquo; and sends an instruction to the ATEM that instigates a MACRO to transition to the active input</li><br />
<li>The web stream is generated by the ATEM Mini Pro and the media server is based on Guy, M0GUY&rsquo;s PiDeck software</li><br />
<li>You can register on the web site to receive a stream key and to be included in the GB3JV SLACK channel. SLACK will alert you to repeater activity so you can join in with a QSO.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Telemetry:</strong></span></p><br />
<p>The repeater&rsquo;s<span class="Apple-converted-space">&nbsp; </span>telemetry system is based on the &ldquo;Modbus RTU&rdquo; protocol over internet protocol this allows:</p><br />
<ul><br />
<li>Full remote monitoring of the repeater&rsquo;s health with notifications to the keeper&rsquo;s iPhone</li><br />
<li>Full remote control of the repeater&rsquo;s functions and status<span class="Apple-converted-space">&nbsp;</span></li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Outputs:</strong></span></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;rtmp://rtmp.batc.org.uk/live/gb3jv</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Inputs:</strong></span></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Networking:</strong></span></p><br />
<ul><br />
<li>The repeater is curently networked using an unlimited 4G cellular tariff provided by "SMARTY" an H3G company.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Latest News (updated 10/07/2022)</strong></span></p><br />
<p><strong>Input Recording:</strong>&nbsp;In August we are launching a new feature: Repeater recording. Those who have joined the GB3JV web site will be able to access any of these recordings via a link. A great way to review your, and others repeater traffic after the event. See the updated privacy policy at&nbsp;<strong><a #0000ff;"><strong>www.gb3jv.co.uk</strong></span></p><br />
<p style="font-weight: 400;"><span style="color: #0000ff;"><strong><span style="color: #000000;">New Ethernet FWA link:</span>&nbsp;</strong></span>Justin&rsquo;s been a bit busy installing a new 5GHz link between his house and the GB3JV repeater. The objective of the project is to replace the 4G Cellular internet connection with an RF (Fixed Wireless Access) link back to my house. It&rsquo;s all about the ROI &ndash; &nbsp;4G Cellular @ &pound;18/month: &pound;120 (equipment) + &pound;50 (License) +&pound;10 (cables) = &pound;180 / &pound;18/month = 10 months.</p><br />
<p style="font-weight: 400;">The link equipment I&rsquo;ve purchased is the Ubiquiti &ldquo;LiteBeam&rdquo; 5AC Gen2. This equipment is often used for Wireless Broadband connectivity in rural areas and can be configured for point-to-point or point-to-multipoint. The photograph shows the installation on my chimney. The cost of the equipment was just &pound;60 per endpoint, including VAT. Supplier: 4gon.co.uk&nbsp;</p><br />
<p style="font-weight: 400;">The equipment provides an ethernet interface at each end and has a comprehensive management system, shown in the attached screen shots. Measured throughput is 30Mb/s the configuration I&rsquo;m using is a 20MHz channel running QAM64 modulation schema (remember&nbsp;this is half duplex!). I&rsquo;ve opted for link resilience over ultimate speed. The unit runs two MIMO (multiple&nbsp;in - multiple out) &nbsp;&ldquo;chains&rdquo; one data stream is horizontally polarised and one vertically polarised. I'm monitoring link performance for a few weeks via my Syslog server instance.</p><br />
<p style="font-weight: 400;"><strong>Spectrum Planning:&nbsp;</strong>The 5GHz spectrum is divided into three bands:</p><br />
<ul style="font-weight: 400;"><br />
<li>Band A: 5150-5350 MHz EIRP 200mW&nbsp;alllowed&nbsp;- no fixed outdoor or airborne use, DFS required above 5250 MHz</li><br />
<li>Band B: 5470-5730 MHz 1W EIRP allowed - no airborne use, DFS and TPC required</li><br />
<li>Band C: 5725-5850 MHz 4W EIRP allowed - Must hold a 5.8 GHz licence and all terminals must be registered. DFS and TPC</li><br />
</ul><br />
<p style="font-weight: 400;"><strong>DFS</strong> =&gt; Dynamic Frequency Selection and <strong>TPC</strong> =&gt; Transmit Power Control</p><br />
<p style="font-weight: 400;">Justin's applied to OFCOM for a Band C &ldquo;light licence&rdquo;, but for now he's using Band B. The move to Band C (avoiding the amateur allocations!) will give another 6dB margin due to the higher transmit power and an additional 5dB margin due to the lower noise floor (as measured).<br /><br />Thanks to Gareth G4XAT for his help with antenna erection!<br /><br /></p></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9928GB3JV2022-07-10T21:32:06Z<p>G8YTZ: </p>
<hr />
<div><div><br />
<p><strong>GB3JV DATV repeater located in Petts Wood, Kent</strong></p><br />
</div><br />
<div><br />
<p><strong>Output: 3.404GHz - 2MS/s - DVBS-2 - 0.35 - FEC 4/5 - Horiz. Polarisation</strong></p><br />
</div><br />
<div><br />
<p><strong>Location: &nbsp; &nbsp; JO01AJ (Petts Wood Railway Station)&nbsp;</strong></p><br />
<p><strong>Web Site: &nbsp;&nbsp;&nbsp;<a href="http://www.gb3jv.co.uk/">www.gb3jv.co.uk</a></strong></p><br />
</div><br />
<p><span style="color: #0000ff;"><strong>GB3JV Overview</strong></span></p><br />
<ul><br />
<li>The repeater uses an innovative new controller system based on the Blackmagic ATEM Mini Pro broadcast switcher and Bitfocus&rsquo; &ldquo;Companion&rdquo; middleware</li><br />
<li>The 70cm and 23cm receivers are based on the &ldquo;Minitiouner&rdquo; hardware, developed by F6DZP and the &ldquo;Ryde&rdquo; software developed by members of the BATC</li><br />
<li>When a signal is received a &ldquo;web-hook&rdquo; command is sent to &ldquo;Companion&rdquo; and sends an instruction to the ATEM that instigates a MACRO to transition to the active input</li><br />
<li>The web stream is generated by the ATEM Mini Pro and the media server is based on Guy, M0GUY&rsquo;s PiDeck software</li><br />
<li>You can register on the web site to receive a stream key and to be included in the GB3JV SLACK channel. SLACK will alert you to repeater activity so you can join in with a QSO.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Telemetry:</strong></span></p><br />
<p>The repeater&rsquo;s<span class="Apple-converted-space">&nbsp; </span>telemetry system is based on the &ldquo;Modbus RTU&rdquo; protocol over internet protocol this allows:</p><br />
<ul><br />
<li>Full remote monitoring of the repeater&rsquo;s health with notifications to the keeper&rsquo;s iPhone</li><br />
<li>Full remote control of the repeater&rsquo;s functions and status<span class="Apple-converted-space">&nbsp;</span></li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Outputs:</strong></span></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;rtmp://rtmp.batc.org.uk/live/gb3jv</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Inputs:</strong></span></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Networking:</strong></span></p><br />
<ul><br />
<li>The repeater is curently networked using an unlimited 4G cellular tariff provided by "SMARTY" an H3G company.</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Latest News (updated 10/07/2022)</strong></span></p><br />
<p><strong>Input Recording:</strong>&nbsp;In August we are launching a new feature: Repeater recording. Those who have joined the GB3JV web site will be able to access any of these recordings via a link. A great way to review your, and others repeater traffic after the event. See the updated privacy policy at&nbsp;<strong><a href="http://www.gb3jv.co.uk/">www.gb3jv.co.uk</a></strong></p><br />
<p style="font-weight: 400;"><span style="color: #0000ff;"><strong><span style="color: #000000;">New Ethernet FWA link:</span>&nbsp;</strong></span>Justin&rsquo;s been a bit busy installing a new 5GHz link between his house and the GB3JV repeater. The objective of the project is to replace the 4G Cellular internet connection with an RF (Fixed Wireless Access) link back to my house. It&rsquo;s all about the ROI &ndash; &nbsp;4G Cellular @ &pound;18/month: &pound;120 (equipment) + &pound;50 (License) +&pound;10 (cables) = &pound;180 / &pound;18/month = 10 months.</p><br />
<p style="font-weight: 400;">The link equipment I&rsquo;ve purchased is the Ubiquiti &ldquo;LiteBeam&rdquo; 5AC Gen2. This equipment is often used for Wireless Broadband connectivity in rural areas and can be configured for point-to-point or point-to-multipoint. The photograph shows the installation on my chimney. The cost of the equipment was just &pound;60 per endpoint, including VAT. Supplier: 4gon.co.uk&nbsp;</p><br />
<p style="font-weight: 400;">The equipment provides an ethernet interface at each end and has a comprehensive management system, shown in the attached screen shots. Measured throughput is 30Mb/s the configuration I&rsquo;m using is a 20MHz channel running QAM64 modulation schema (remember&nbsp;this is half duplex!). I&rsquo;ve opted for link resilience over ultimate speed. The unit runs two MIMO (multiple&nbsp;in - multiple out) &nbsp;&ldquo;chains&rdquo; one data stream is horizontally polarised and one vertically polarised. I'm monitoring link performance for a few weeks via my Syslog server instance.</p><br />
<p style="font-weight: 400;"><strong>Spectrum Planning:&nbsp;</strong>The 5GHz spectrum is divided into three bands:</p><br />
<ul style="font-weight: 400;"><br />
<li>Band A: 5150-5350 MHz EIRP 200mW&nbsp;alllowed&nbsp;- no fixed outdoor or airborne use, DFS required above 5250 MHz</li><br />
<li>Band B: 5470-5730 MHz 1W EIRP allowed - no airborne use, DFS and TPC required</li><br />
<li>Band C: 5725-5850 MHz 4W EIRP allowed - Must hold a 5.8 GHz licence and all terminals must be registered. DFS and TPC</li><br />
</ul><br />
<p style="font-weight: 400;"><strong>DFS</strong> =&gt; Dynamic Frequency Selection and <strong>TPC</strong> =&gt; Transmit Power Control</p><br />
<p style="font-weight: 400;">Justin's applied to OFCOM for a Band C &ldquo;light licence&rdquo;, but for now he's using Band B. The move to Band C (avoiding the amateur allocations!) will give another 6dB margin due to the higher transmit power and an additional 5dB margin due to the lower noise floor (as measured).<br /><br />Thanks to Gareth G4XAT for his help with antenna erection!<br /><br /></p></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9927GB3JV2022-07-10T21:15:33Z<p>G8YTZ: </p>
<hr />
<div><p><span style="color: #0000ff;"><strong>GB3JV Overview</strong></span></p><br />
<p>The GB3JV Amateur TV repeater is located at Petts Wood Roadway station, at JO01aj.</p><br />
<p><span style="color: #0000ff;"><strong>Outputs:</strong></span></p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;rtmp://rtmp.batc.org.uk/live/gb3jv</li><br />
</ul><br />
<p><span style="color: #0000ff;"><strong>Inputs:</strong></span></p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9926GB3JV2022-07-10T21:15:03Z<p>G8YTZ: </p>
<hr />
<div>GB3JV Overview<br />
<br />
The GB3JV Amateur TV repeater is located at Petts Wood Roadway station, at JO01aj.<br />
<br />
Outputs:<br />
<br />
3.404GHz, 2Ms/s FEC 4/5<br />
BATC Web Stream: rtmp://rtmp.batc.org.uk/live/gb3jv<br />
Inputs:<br />
<br />
DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection<br />
DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection<br />
BATC Web Stream, please limit your stream to 800kb/s<br />
144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9925GB3JV2022-07-10T21:13:14Z<p>G8YTZ: </p>
<hr />
<div><p>GB3JV Overview</p><br />
<p>The GB3JV Amateur TV repeater is located at Petts Wood Roadway station, at JO01aj.</p><br />
<p>Outputs:</p><br />
<ul><br />
<li>3.404GHz, 2Ms/s FEC 4/5</li><br />
<li>BATC Web Stream:&nbsp;rtmp://rtmp.batc.org.uk/live/gb3jv</li><br />
</ul><br />
<p>Inputs:</p><br />
<ul><br />
<li>DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection</li><br />
<li>BATC Web Stream, please limit your stream to 800kb/s</li><br />
<li>144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</li><br />
</ul></div>G8YTZhttps://wiki.batc.org.uk/index.php?title=GB3JV&diff=9924GB3JV2022-07-10T21:09:58Z<p>G8YTZ: Created page with "GB3JV Overview The GB3JV Amateur TV repeater is located at Petts Wood Roadway station, at JO01aj. Inputs and outputs: Outputs: - 3.404GHz, 2Ms/s FEC 4/5 - BATC Web Stream:..."</p>
<hr />
<div>GB3JV Overview<br />
<br />
The GB3JV Amateur TV repeater is located at Petts Wood Roadway station, at JO01aj.<br />
<br />
Inputs and outputs:<br />
<br />
Outputs:<br />
- 3.404GHz, 2Ms/s FEC 4/5<br />
- BATC Web Stream: rtmp://rtmp.batc.org.uk/live/gb3jv<br />
<br />
- DVBS/S2 1249MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection<br />
- DVBS/S2 437MHz/Horiz. 333kS/s or 2MS/s, automatic FEC detection<br />
- BATC Web Stream, please limit your stream to 800kb/s<br />
- 144.750 FM/Vertical 103.5Hz CTCSS (ATV Calling Channel Talkback frequency)</div>G8YTZhttps://wiki.batc.org.uk/index.php?title=UK_ATV_repeaters&diff=9923UK ATV repeaters2022-07-10T21:01:05Z<p>G8YTZ: </p>
<hr />
<div>There are over 30 active ATV repeaters in the UK and the current status and operating frequencies can be found on the [https://www.ukrepeater.net/repeaterlist5.htm RSGB ETCC TV list]<br />
<br />
Here are two printable .pdf maps of TV Repeaters in the North and South of England: [[:Media:RptrNorth.pdf|Repeaters North]], [[:Media:RptrSouth.pdf|Repeaters South]]. These can be printed double-sided, landscape, flipped on the short edge.<br />
<br />
You can watch most UK ATV repeaters on the [http://www.batc.tv/ch_live.php BATC video streaming service.] <br />
<br />
[[File:tvrepeaters.JPG|400px]]<br />
<br />
All repeaters have a seperate page which the group can now edit to add information.<br />
<br />
*[[GB3AT]]<br />
<br />
*[[GB3BH]]<br />
<br />
*[[GB3CT - Caistor IO93UM]]<br />
<br />
*[[GB3ET]]<br />
<br />
*[[GB3EY - Near Hull IO93RS]]<br />
<br />
*[[GB3FT]]<br />
<br />
*[[GB3GG]]<br />
<br />
*[[GB3GV]]<br />
<br />
*[[GB3HV]]<br />
<br />
*[[GB3JT]]<br />
<br />
*[[GB3JV]]<br />
<br />
*[[GB3KM]]<br />
<br />
*[[GB3LO]]<br />
<br />
*[[GB3LX]]<br />
<br />
*[[GB3NQ]]<br />
<br />
*[[GB3NV]]<br />
<br />
*[[GB3PV]] Cambridge<br />
<br />
*[[GB3SQ]] Bournemouth<br />
<br />
*[[GB3TM]]<br />
<br />
*[[GB3TN]]<br />
<br />
*[[GB3TT - Sheffield IO93gk]]<br />
<br />
*[[GB3UD]]<br />
<br />
*[[GB3UT]]<br />
<br />
*[[GB3YT]]<br />
<br />
*[[GB3VL]]<br />
<br />
*[[GB3ZZ]]</div>G8YTZ