I've been given a handful of wireless microphones that transmit in the 36 MHz band, but unfortunately no receiver was included and proper receivers for that wireless mikes seem to be crazy-expensive.
I've taken at look at the RF with a scope and it looks a lot like simple FM with a pilot tone.
I'm guessing that the pilot tone is used only to detect if a channel is being used and not drowned in noise, so the receiver can squelch the noise.
Does anyone know how the audio is modulated?
I'm looking around for a simple, cheap FM receiver that I can modify to receive the mike signal and I've noticed that 36 MHz RC receivers are insanely cheap, so I'm thinking that I ought to be able to grab the demodulated analog signal before it enters the digital RC part of the receiver and pass that off to my own low pass and squelch circuit.
Any better suggestions for a source of cheap 36-37 MHz FM receivers?
Best Answer
Personally, I would try to mod stardand single-chip FM radio receivers (ones which usually work at 100-108Mhz range) with higher values in it's input circuit.
Easiest & cheapiest way to test this would be mod working chineese 1$ FM radio and see if it would work on lower freq.