I'm not too worried about microphones picking up too much background noise... my Chase Cam microphone mounted on the passenger side floor is able to pick up most everything I say from several feet away in a noisy race car, with my full face helmet on. I know that Chuck has tucked his microphone into his helmet with good results too.
My main concern is with the earpiece being loud enough to hear it in a noisy race car. I think this is the main problem for us. I've found that just driving my race car on the highway on my way to an event is too noisy for the Bluetooth headset I have... people can seem to hear me alright, but it's really hard for me to hear them. Having a helmet on should help, but race track conditions are also going to be a lot louder than driving on the street.
My gut feeling is that FRS/GMRS radios could work better for us, being that they are cheap, readily available, there would be no dropped calls (imagine trying to re-dial as you race around the track), and we could wire up custom headsets and microphones if we needed to. I could even make my video record our funny conversations on it's spare audio channel (which could also easily be removed later if we wanted too). The problems would be range (they say 5 miles, but that's with flat land and nothing in between the two radios), and the possibility of other people using the same frequencies. Maybe we could mount a small external antenna on our cars to help the range issue though (I've seen other race cars do similar things).
The radios have anywhere from 7 to 22 channels, so it wont be a big problem, but we would just need to make sure we don't pick the same channel as someone else. I know that some NASA officials (ie Chuck, Kevin, etc) are using what look like FRS or GMRS radios, but last I knew, race control was using more professional radios on a completely separate and dedicated frequency. So, at worst, we have to listen to Kevin heckling us. The privacy code feature is pretty much useless... you're still on the same actual frequency, so you'll still interfere with other people; it's just that you're transmitting a specific tone that other receivers with the same privacy code are listening for. In my experience, interference or static will screw up that tone, so other people may not hear you at all. Unless you have really good conditions, it's best to just set it to zero, which turns that feature off so that you hear everything on that channel.
I suppose another idea would be something based on a CB radio transceiver... 40 channels, optional sideband channels, and there shouldn't be any range issues for us. We'd just have way more of an issue with other people using the same frequencies, especially if we're near a trucking route or in a rural area, which applies to pretty much all of our tracks.
