EDIT: (Ahhh, didn't see the "Good to Go" part in your post, just saw the "Need to get a better understanding" part) -- Selective reading FTW
As I understand it, with my limited time in the Huey, you should be able to get all of the frequencies in Sparky's list (see Squad Freqs post) on Radio 3 (the lowest one of the 3 on the left).
To do that, the Radio needs to be powered up, and your Intercom switch (below the radios) needs to be switched to Intercom position 3. At that point, tuning the radio and setting the volume should allow you to work with those frequencies.
That said, I'm by no means an expert on that bird, so take this post with as much salt as you need, but that's the way I'd be trying it. The radio should cover the desired frequency range as far as I can tell.
Regards,
4 ~S!~