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.

The station currently houses the following facilities available for use by anyone worldwide:

• Qatar Oscar 100 Narrow Band WebSDR - https://eshail.batc.org.uk/nb/

• Qatar Oscar 100 Wide Band (DATV) spectrum monitor - https://eshail.batc.org.uk/wb/

• AMSAT-UK Funcube ground station

• The Goonhilly VHF websdr https://vhf-goonhilly.batc.org.uk/

• Kiwi HF WebSDR with GPS TDOA

More recent photos of the equipment taken by M0DNY during a maintenance visit on 19 March 2021:

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:

• 10MHz & 25MHz Leo Donar GPSDO Settings screenshot

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"