There are currently two WebSDRs (web based radio receivers) located at the bunker and available for public use. We do our best to keep electrical noise and interference to a minimum, but from time to time activities may disrupt that.
Occasionally the internet connection may drop. There is very little we can do to prevent this, but, if you notice the SDRs are offline for extended periods, you may contact us and we’ll look into it.
HF SDR: http://sdr.gb0snb.com:8073
Currently offline for repair
VHF SDR: http://sdr.gb0snb.com:8074
The VHF, UHF and SHF receivers, commonly just the VHF SDR, is a custom made RF front end with helical bandpass filtering for each amateur band listed below. A low-noise front end preamp (based around the MiniCircuits PGA-103+) is employed which does its best to recover weaker signals. Helical filtering tries to keep out-of-band strong signals (of which there are many) from causing issues with the five RTL-SDR V3 dongles used on each band. The antenna is currently a Diamond V2000A at 45m above ground (~135m above sea). The bands and frequencies covered are listed below; bands marked with an asterisk (*) may later be configured to have switchable segments within the band.
- 6m (50 – 52 MHz)
- 4m (70 – 72 MHz)
- 2m (144 – 146 MHz)
- 70cm (432 – 434 MHz)*
- 23cm (1296 – 1298 MHz)*
Bands are run simultaneously so any changes you make do not affect other users.