An important aspect of APRS is making you are on frequency. If you’re off, then there is not going to be anyone out there to decode your packet. All APRS activity is done on Upper Side Band (USB). Here are the most common frequencies used on HF APRS with the use of the Vara modem:

7.083.5 mHz – this 40 meter frequency can get quite popular when the conditions are good. I have shared APRS chats with stations 3000 miles away. Mobile experiments through the PacNW area of the US has shown Zero missed packets.

14.103.0 mHz – this 20 meter frequency is much more popular in Europe than in the US. It’s a great option if you’re on the east coast of the US to reach out across the Atlantic for some DX.

10.147.60 mHz – There is only one station I know of that is pretty constantly using 30 meter APRS. This is the same frequency used by standard AX.25 APRS so you will hear mixed traffic

5.403.5 mHz – 60 meter “Channel 5” is also a shared frequency. Again, I only know a single person that uses 60m for Vara APRS.

A great way to be successful is if you can narrow your SSB width. VaraHF operates within 500hz. I like to narrow my SSB width to 600hz. This will help cut down on other interference and also give a little bit of wiggle room if someone is slightly off frequency.