Using Bias-T on an Airspy R2 via spyserver

Terry Gaff

Hi all,

I've successfully set up my first spyserver using an Airspy R2, it's working great. From it's location, certain signals that I'd like to monitor (and decode) will require the use of an LNA.. others do not. I intend to use an LNA design that uses an MMIC device that maintains the RF path even when it's not powered. This will allow me to receive signals if the LNA is powered on or off. Given that SDR# with spyserver doesn't seem to allow the bias-T on the remote Airspy R2 to be switched on or off 'on the fly' (I know I can switch it on or off by remotely accessing the R.Pi and editing the spyserver.config file and then restarting spyserver, but this obviously is very cumbersome).

Having the ability to remotely switch on and off the remote bias-T in spyserver mode (as we can with a local airspy device), would be great... Are you listening Prog ???
Failing that, or, until then... Has anybody else come up with a solution for this issue ?

I am thinking of using a relay module, controlled by one of the R.Pi GPIO pins (operated by a phone app.. 'RaspController'), to allow 5V to the LNA via a separate bias-T.. doable, but again a little cumbersome. I'm also thinking that remotely operating the bias-T might offer other possibilities, including switching between two antennas. Would be very handy at a remote site not often visited etc.

Many thanks for any thoughts on this.

Terry Gaff