I would start by removing the Mic DC from the exciter. I inject the audio to pin 22 on the top row of pins on the backplane that goes to the exciter interconnect board. I also cut the trace on the backplane board that goes to pin 22, so that the only source of audio reaching the exciter comes from the controller.
Assuming that you are using the factory PL decoder and encoder, I have found a decoder now and then that either has a bad coil or capacitor and is not filtering all of the PL out of the receive signal. These modules are getting on towards 30 years old and you can find a bad part every now and then. Look at the output of pin 17 of the squelch gate module with a scope and make sure the PL filters on the PL decoder are doing their job. You should not see any PL on the audio at this point. This is where I also pick up receive audio to feed into the controller. I will use a series capacitor or a series/parallel resistor capacitor combination in the receive audio lead at times to get the proper audio response curve to the controller input. Joe - WA7JAW --- In Repeater-Builder@yahoogroups.com, "n6nr" <[EMAIL PROTECTED]> wrote: > > I am having a problem with the audio coming from my remote base > receiver. I am using a LINKR2A controller. I originally used the de- > emphasis jumper setting, but it sounded too treble, so went back to > the broader spectrum setting. > > The problem is that I have to take the audio directly off of the > remote receiver's discriminator, rather than using filtered audio. I > currently inject audio from the ICS controller to the exciter on pin > 11 of the Squelch Gate card, which is a filtered input. However, when > RX audio from remote receiver has PL superimposed on it, it still > interferes with the repeater's talkback PL. > > It looks like I may have to build an RC filter of my own to clip off > the PL before it gets to the controller. Does anyone have a > suggestion as to a better place to inject the audio? >
