I'm a photographer for one of the TV stations that has a chopper and it's rare to hear MPD talk to the other helo pilots on the helo channel talk around.
I think I've heard them once...and that was when they were asking for help looking for someone....they wanted another set of eyes looking for some guys running.
They are busy when they're up with ATC as well as MPD comms.
I work at 3 and we communicate back to the station by UHF. I can only think of one time in the past 6 years where we have used the microwave to talk back to the station. The nice thing about the microwave is that it's secure and the other stations can't easily listen.
The freq escapes me now...it's UHF. I'm not sure if the one in the database is right.
And I've noticed that all other choppers around in the air do communicate on the talk around channel. Anytime we are up and 5 is up the piolts communicate a lot....especially since they are so close. So you should hear lots of chatter. And they talk back to the station UHF as well.