SUWS WebSDR

The SUWS Farnham WebSDR is a web-based multi-user remote radio receiver, designed to let anyone tune in and listen to Radio signals received by the Array of Antennas installed at 30m AGL just north of Farnham, Surrey.

The WebSDR can be accessed at: http://websdr.suws.org.uk/

About

WebSDR Mast + Equipment Shed

WebSDR Mast + Equipment Shed

SUWS originally started looking on-campus in Southampton for a site for a remote receiver to allow members with disadvantaged home locations to listen to local signals, however roof access to University Buildings proved extremely difficult. Noel G8GTZ offered a location at his remote station on a hill near Basingstoke, and Martin G8JNJ built several VHF/UHF antennas for the WebSDR. In August 2014 however the land of the hill changed hands, and we moved to a new site at the location of GB3HV in Surrey.

Current Location

The new location is on a ridge just north of Farnham, using an old 1950s MOD Ground->Air Communications Mast on the site of Tech Recycle.

Hardware

Radio

  • 10GHz Slotted Waveguide Antenna (Horizontal Omnidirectional)
    • Masthead Octagon PLL LNB downconverting to 618MHz
    • G8JNJ-modified R820T Dongle on 618-620 MHz (10.368 – 10.370 GHz)
  • G8JNJ 434MHz Omni-polarised Helix Dipole (Info)
  • G8JNJ 145MHz Omni-polarised Helix Dipole (Info)
  • G8JNJ Wideband Active Antenna (Info)
    • R820T2 Dongle, Direct Sampling on 0-2 MHz

PC

Thanks to University of Southampton Electronics and Computer Science Faculty for donating the high performance PC!

  • Xeon W3520 2.67GHz
  • 12GB ECC RAM
  • Supermicro Motherboard

Internet Connection

We currently have our own reliable internet connection, with dedicated IPv4 and native IPv6 allocation! This is courtesy of TxRx Communications with whom we share use of the mast.

NTP Server

As a side-project, there is a Raspberry Pi on-site with ntpd listening to a HAB Supplies ublox MAX-7 GPS, providing a high quality GPS-PPS-synced NTP Server.

This ntp server is accessible on both IPv4 and IPv6 at: ntp.suws.org.uk

It has also been registered in the UK Public NTP Pool. IPv4 StatsIPv6 Stats

Those of you enlightened with IPv6 access can see a graph of ntpd’s PLL loopstats at: http://[2a05:5241:100:4000:ba27:ebff:fe04:ccd4]/

  • (It can be interesting to note when the shed has been accessed, the rapid change in air temperature causes a ~10us perturbation in the PLL error!)