Originally Posted by farsouth
If the "upper VHF bands, into the 140's" that paragliders use are the Amateur Radio frequencies (144-146MHz in UK), then the problem is that aircraft VHF transceivers use AM whereas the Amateur bands (and Marine/Police etc) use FM. You will not find a transceiver that works on both modes. FM receivers can receive aircraft AM transmissions, but for transmitting, it has to be the right system. (As far as I know.....)
Yes, but its seems to me (a relatively non-technical person) that if FM transmitter/receivers can receive AM transmissions they ought to be able to send in AM as well. Or is it more complicated than just adding another component into the case?!