I'm trying to build an AM transmitter to remotely listen to sounds within a fairly small distance from the microphone (<30m). One thing I wanted to try was to use the microphone jack on my laptop to pick up the signal. The idea is that I could pick up all signals (my laptop can record up to 192,000 samples per second) and have the transmitter transmit at a frequency such as 48khz. I could then demodulate the signal in software. I figure this could reduce costs and it should be fairly easy to pick up RF frequencies through the microphone jack. The main issue is that the transmission frequency would be very low.
My questions are:
- Is it practical to transmit audio at such a low frequency?
- What can I expect in terms of signal quality?
- What can I expect in terms of signal range at this frequency (the transmission power would probably be around 100mw)?