Operate WSPR, WSJT, PSK31 remotely over Linux

When operating digital amateur radio modes remotely (i.e. controlling distant transceiver over the internet) it’s best to have the computer generating the tones local to the radio. That is, you should run VNC or Remote Desktop software connected to the remote PC, running the programs on the remote PC. You can do this even over very limited « 1 Mbps connections.

Running ham radio digital modes over VNC

It’s best to use VNC so that even if your internet connection drops, the program stays running (particularly for WSPR).

How to configure VNC to run any program remotely

If you use RDP (Windows Remote Desktop) to remote digital mode ham radio PC, be sure to NOT redirect audio, as you may disrupt the audio to the remote program.

For remote stations where line-of-sight links exist, it is possible to pass audio over radio links with proper care. Although today’s broadband audio codecs used over the Internet give better fidelity, are you sure that:

  1. phase continuity is assured (particularly for PSK modes)
  2. frequency resolution is high enough (particularly for narrowband FSK modes like WSPR and WSJT)

Typical VoIP uses UDP, which simply drops missed packets. UDP overlays that buffer and rerequest can lead to time sync issues, particularly for tightly time-synchronized modes like WSPR and WSJT.

In short, remote tone generation might work somewhat, but performance will suffer.

Additionally, audio dropouts on digital modes cause interference to adjacent spectrum.