Gentelmen ….. sometimes I attend events that involve private aircraft and event communications are on multiple VHF frequencies …. and I’m at these events with up to 20 friends ….. what I’ve got in mind is an RF/audio system that takes the audio output from multiple (maybe up to four) pocket size VHF receivers, runs those outputs thru a passive mixer, and that output goes to a Bluetooth dongle ….. or dongles, as the case may be …… I’ve considered running the mixer output to a low power FM transmitter but everyone seems to already has Bluetooth ear pieces or headsets …. and dongles are inexpensive ….. and their 30 foot range is more than adequate ….. the VHF receiver headphone audio output is via a 3.5 mm stereo jack ….. the audio, when the receiver is in the VHF mode, is mono and of limited frequency response … nothing fancy ….. each VHF receiver has its own self-contained battery so no power requirements there …. the mixer is passive so no power requirements there …. so I just need 5 volts for the dongles …. that’s easy …. LM7805 …. looking at the USB 3.0 pinout – I’ll need to use pins 1 and 4 for power and connect the mixer audio output to pins 8 and 9 and ground (pin 4) …. the question of the day is – “What electronics do I need to insert between the analog audio mixer output and dongle pins 8 and 9 ???” ….. probably will include an A to D converter ....
Thanks ….
Thanks ….