Es'hail-2 Ground Station
The BATC & AMSAT-UK QO-100 (Es'hail-2) WebSDR & Spectrum Monitor are located at the iconic Goonhilly Earth Station in Cornwall (IO70JB).
The equipment is housed in a room dedicated to amateur radio infrastructure in the workshops building for the now defunct GHY2 90 ft dish antennae, built in 1969.
As well as the Es'hail-2 (now known as Qatar Oscar 100) WebSDR and spectrum monitor, the station houses an AMSAT-UK Funcube ground station, the Goonhilly VHF websdr and an HF Kiwi WebSDR with GPS TDOA.
RF System
Dish
The original dish installed in August 2018 was a consumer model and suffered damage in strong winds during October 2018.
This was replaced in January 2019 with a heavy duty Hirschmann 1.3m offset dish.
RF Front End
A modified Octagon quad LNB is mounted on the dish and locked to the 25 MHz output from a Leo Bodnar GPSDO.
See https://wiki.batc.org.uk/Es%27hail-2_LNBs_and_Antennaes for more details on the locking modifications
The 25 MHz reference is fed to the LNB through a dedicated coax run, and 2 further coax runs are used to feed separate horizontal & vertical feeds back to the equipment room.
Receivers
2 separate AirSpy USB SDR Receivers, locked to a 10MHz output from the LeoBodnar GPSDO, are used for the WebSDR and Spectrum monitor.
GPS reference
The GPS reference is a Leo Bodnar unit, running firmware version 1.12, programmed to produced 10 MHz (for the Airspys) and 25 MHz for the LNB. The settings for the reference to produce these 2 frequencies were not straightforward (as the 2 outputs on the Leo Bodnar unit need to be linked) but are here for reference:
Computer System
Hardware
The WebSDR & Spectrum Monitor both run off a single machine with the following hardware specification:
- Intel i7-2600 CPU
- 16GB DDR3 RAM
- Intel DQ67SW Motherboard
- 500GB Samsung 850 EVO SSD
Software
- Ubuntu Server 18.04
- Nginx Web Server & Reverse Proxy (github-webpages)
- Narrowband resampler 2.5MS -> 512Ks (github)
- Narrowband WebSDR by PA3FWM (homepage, github-configuration)
- Wideband Transponder FFT Spectrum Server (github)
- Chat Server (github)
Networking
Goonhilly Earth Station has 2x diverse redundant 10Gb links into London Datacenters through Next Connex. They have been kind enough to give us a dedicated IP address and access to >300Mb/s of up & down bandwidth for use by the station.
A pfsense firewall running on a PC Engines APU2D4 board is used as the station router & firewall.
A high-bandwidth Leo Bodnar NTP Server provides NTP service to the station & the worldwide NTP Pool. Stats and graphs of this service can be viewed at https://eshail.batc.org.uk/ntp/
Using the Wideband spectrum monitor and Narrow band SDR
Wideband monitor
The Wideband Spectrum Monitor can be accessed at https://eshail.batc.org.uk/wb/
To log in, type the following in to the box at the bottom of the chat (replacing "my name" with your real name or callsign) and press return:
/nick my name
For example:
/nick G8ABC_Fred
You will get a confirmation message that your name has changed and the text in the box changes to "Type a message here and press enter" - your name also appears in the list on the right handside of the page.
Narrow band SDR
The Narrowband WebSDR can be accessed at https://eshail.batc.org.uk/nb/
This user guide written for the Farnham websdr gives a detailed description on how to use the web sdr http://farnham-sdr.com/WebSDR-User-Guide.pdf
The chat facility is actually an dedicated IRC channel and to access it, enter your name or callsign in the "nickname" box, tick "I am not a robot and press "connect"