Hi Malcolm,
I have been using VarAC on HF and recently got interested in using it on 2 meters.
I have just finished validating my 2 meter set up and here is what I can tell you:
(Everyone – Please correct me if I am in error or elaborate if clarification will benefit)
1) Does or can it [VarAC] work on 2m and or 70cm? – Yes
2) Does or can it [VarAC] work on/with a 7300 Icom? – Yes, but you have to figure out how
3) How to change and use the VarAC frequency list? - Edit with Notepad
On topic #1: Included in the VarAC setup is the VARA modem type menu to select either VARA HF or VARA FM. You will use VARA FM for 2 meters or 440. If you have a radio with both HF and 2 meter capabilities you will need to change the VARA modem type each time you switch between HF and FM operation, or “simply” make two separately VarAC program folders which will each retain their different configurations.
A related but different point; I have separate VARA FM program folders for use with Winlink and VarAC on 2 meters, because Winlink has no PTT control and I rely on VARA FM to control that function, whereas I do not want VARA FM attempting PTT control when I use it with VarAC.
On topic #2: If your radio has provision for external speaker and microphone, as well as external PTT, then – Yes - your radio will work. A “sound card” is necessary. It may reside in your computer or your radio (if so equipped), or between them (ala Digirig or Signalink). Your radio may offer connections for audio in and out in addition to external speaker and microphone which may be less of a chore to use. You will find the specifics in your radio’s manual.
If your radio has CAT control, then either VarAC or VARA FM can be used to control frequency and PTT. Here are the VarAC setting related to PTT and frequency control that I used because my radio has no CAT control. If yours does offer CAT controls, you will find other references to be of value configuring them.
If your radio does not have CAT control (like my FT-7800) then you will set up PTT to function from the computers COM port similar to what is shown in my VarAC settings above. If you do set VarAC to control PTT via the COM port DTR/RTS, you must turn off VARA FM PTT control capability. I found setting VARA FM PTT control to VOX was sufficient, but there may be a better selection.
On Topic #3
You may choose to add 2 meter frequencies the VarAC frequency list, however I have found no standard VarAC 2 meter calling frequencies. If your radio accepts VarAC frequency control via CAT, then I expect VarAC will use the existing frequency list to which you add 2 meter frequencies.
Look in your VarAC program folder for the file ‘VarAC_frequencies.conf’ and edit it with Notepad. It’s there, but it’s not a .txt file. A suggestion: edit the file ‘VarAC’ (no extension) of File type “Configuration Settings” as well, and change it to read “LastFrequencyLoadUponStartup=ON”.
If you do not have CAT control, the frequency list you edited will serve only as a reminder of favored frequencies to which you must manually tune your radio. (Does anyone know how to turn off the annoying reminder every time VarAC is started without CAT?)
Hopefully my experience will be helpful to you or others.
-Jeff AJ6LG
