I'm using an Adafruit Feather M0 Express to build a fox transmitter. The radio I'm testing with is an old Radio Shack HTX-202. I have the PTT circuitry working fine. However, I'm having issues with audio levels. The microcontroller I'm using can play WAV files, and I can hear the output in headphones pretty well. But, when I connect that to the mic input of the transmitting radio, the audio on the receiving radio is extremely weak. It's there and understandable, but just weak.
So, my question is about mic audio levels. On the HTX-202 in particular, but also on the "average" HT in general: what voltage levels are required on the mic input to get good audio quality transmitted by the radio?
It's also a strong possibility that I have a wiring issue and not a voltage-level issue. Electronics is not my area of expertise and I'm basically making this up as I go....
If anyone has done this -- built a fox transmitter with an Arduino-ish board -- please share how you did it! Thanks!!
-Farren