Note, there are two ways to use TARS and TS PTTs. You can either do the above and press the TARS keys to select which radio your normal TS PTT will broadcast on.

Or, you can use the more realistic method and just use the TARS keys to actually transmit over the relevant radio.

For example, if you set the TARS binds to Control + 1 for UHF, Control + 2 for VHF/AM and Control + 3 for VHF/FM. You can press Control+2 once and then use your normal TS PTT to talk on that radio. If you then want to talk on UHF, you'd need to press control + 1 to switch the TS PTT to talk on that channel. This methods is generally used, either, by people who have a very limited number of buttons on their stick/HOTAS or by people who don't know about the following.

The way I (any many others) use TARS, is to ignore the normal TS PTT altogether. I have my WH mic switch buttons bound to TARS for the respective radios as per real life, so mic switch down for UHF, forward for VHF/AM and back for VHF/FM. You just use them as 3 seperate PTTs for 3 seperate radios. As long as you are in the cockpit and TARS is running their is no need to touch the PTT button you have bound in TS. You'll only need the normal TS PTT when outside of the pit, or not running TARS.

Eddie,

When using the method you described, doesn't that also activate the in-game radio menus?

Not if you change the key mappings.

I have the in-game radios mapped to 1, 2 & 3 on the keyboard. I only really use them to call tankers & AWACS, and sometimes ATC for wind info anyway.

I personally remapped my TS3/TARS PTT using the TARS control panel to act like the real A10 with my Warthog Hotas:
Mic Switch FWD VHF AM transmits over TS3/Tars
Mic switch down UHF transmits over TS3/Tars
Mic Switch aft VHF FM transmits over TS3/Tars
I also remapped the in game comms menu to use a modifier(the modifier is the pinky lever on the warthog stick)
Modifier/Mic Switch FWD VHF AM ,menu pops up
Modifier/Mic switch down UHF menu pops up
Modifier/Mic Switch aft VHF FM menu pops up
This is using the latest beta 15 of TARS