I think I figured this out. Everything is wired correctly (see below). The issue is that the recorder has an extremely wide dynamic range, handling line level to mic input levels. It appears that the "AGC" looks at both channels, and adjusts both based on the "loudest" --- so if I have a large audio line input on one side (R), and a small mic input on the other (L) , the gain is set for the line and suppresses the mic into the noise. If I turn the volume down on the HT audio, the mic input comes up out of the noise.

So I need a better, adjustable "pad" for the line level audio coming from the HT (better than the attenuating patch cable I am using)-- I was thinking of a "pot" divider with the input on the outer terminals, and the output off of the center pin--- should I use a big (100K) or small-value (100) pot? Linear, audio, or log taper?

Bill W1PA

-----Original Message----- From: Bill Acito W1PA Sent: Thursday, July 28, 2011 4:55 PM To: amsat-bb@amsat.org Subject: Pin assignments on a stereo mic input?

One more for today... I am using a stereo digital recorder for logging. It has a stereo 3.5mm mic socket. I am using a "attenuating" patch cable from the HT audio into a "stereo splitter" plugged into the mic input (it has a stereo plug, and two mono sockets --- tip and base, and ring and base). The other side of the splitter has a mic. So the intent it to put the HT into one channel, and the external mic (recording me) into the other channel, when recording.

I am only hearing the HT audio on playback. I have a feeling that the plug "base" connection is not ground -- it is on the ring or tip.

Any one have or know the signal assignment on a recorder mic jack? base, ring , and tip? I would assume it would also match the assignment of the mic input of a PC (if you know that)?

Bill W1PA