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: even if the internet connection drops, the program stays running (particularly for WSPR). The VNC server is configured 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.

Problems with remote audio: for remote stations where line-of-sight links exists, it is possible to pass medium-fidelity audio over radio links with proper care. Although broadband audio codecs used over the Internet give better fidelity, consider if:

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

Even gigabit Internet links are subject to VoIP packet drops. 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.