In reading the SatPC32 manual, section 3.C.bb, I see that SatPC32 provides an automated way to switch the antenna feeds by outputting a high or low on the DTR pin of the radio 2 com port through a transistor to switch a coaxial transfer switch. Is there any other way to do this if you are not using a traditional serial port but USB ports or virtual ports?
My setup has a Yaesu radio for TX and an SDRplay for receive. When switching from V/u to U/v, it is necessary to swap the antennas and I would like to do this automatically with a coaxial transfer switch. As above, SatPC32 can do this in automated fashion. However, I am not using a DB9 com port for either radio (USB or internal ports only) and am trying to figure out how to get access to this DTR signal to use it for the automated switching. Has anyone used an SDR for the downlink and set up automatic antenna swapping and if so, how was it accomplished?