VU3ZNG Open WebRX: Covering Satellite Bands!

Web SDR is a software defined radio which can be tuned by multiple users simultaneously from anywhere in the world using internet connectivity to the radio, over a web browser. There are several types of WebSDRs out there, of which Open WebRX is one which I have started noticing only recently. One in my region is run by VU3WEW and covers HF Amateur Radio bands and the 11m Citizen Band. Recently VU3CDK reported that he could hear audio as well as view the waterfall display which was moving laterally due to Doppler effect in a high elevation pass of International Space Station on VU3ZNG webSDR located at Bengaluru, which is the only UHF/VHF webSDR in India.

Open WebRX of VU3ZNG also covers all the amateur radio HF bands as well as 6m band and Citzen band, in addition to satellite bands. There are bookmarks for the various amateur radio satellites so that anyone wishing to listen to them can easily tune in the frequency just by clicking on the bookmark. Satellites with uplink on UHF and downlink on VHF (U/V satellites) like PO-101 and AO-91 are available in the VHF section. Most other satellites with uplink on VHF and downlink on UHF (V/U satellites) are available in the UHF section. Earlier the location of ARISS was at an edge of the UHF band as it was on 437.800 MHz.

Now a separate section has been created and named UHD ARISS which brings it to the center of that band. When the satellite is not in range, a thin marker line can be seen on the waterfall. I noted a delay after choosing the band and display on the waterfall, which is most likely the time needed for my action to be conveyed to the Open WebRX over the internet.

Tried listening to an ARISS pass today morning using VU3ZNG OpenWebRX. But it was an Eastern pass with only about 27 degrees maximum elevation in this region. I could not hear any signals, possibly because of two reasons. First beeing that it was an early morning pass at 4.49 am when local amateur radio operators would have been asleep.

Secondly, even if there were operators from countries on the Eastern side, it would have been a low elevation pass for them and the signals picked by the omnidirectional antennas of the webSDR might have been low. Anyway VU3ZNG OpenWebRX can be an option for those without a full duplex radio as an additional RX only ‘radio’ while trying to access good elevation passes of International Space Station, provided that they are somewhat near to Bengalaru. It can be accessed in the browser of a mobile phone while going portable.

Here is part of the audio recording made by VU3CDK using VU3ZNG Open WebRX during a high elevation pass of International Space Station: