Hi Guys,
I also need to tap my VHF A5 Spectra to decode data transmissions, mainly railroad related apps. From the discussion above, and elsewhere, I've gotten the fact that I need to utilize Pin 11 for the detected audio. However, there are some other caveats that I need to tackle. To get a better idea of what I am doing, I need to have the discriminator feed output to a Griffin iMic, into my computer for the decoding process (done my a monitoring application on the computer). So I need the output to end up on a 1/8" phono jack, to plug into the iMic, routed USB to the computer..
So here are my assumptions. I need to take pin 11 to the positive lead on the jack, and bring the negative lead back to digital ground on pin 8. I think there is supposed to a capacitor in-line here on the postive lead, and possibly a resistor. If so, what are the values? and what other issues do I need to be aware of? My current DB-15 connector only has 4 wires in it. A jumper wire from pin 2 (Emergency) to pin 8 (dig. ground), a positive power wire to pin 5, and speaker wires to pin 6 and 7.
Any help would be greatly appreciated.
Rick