Batboard

I've been searching here on Batlabs and haven't come up with the answer so hopefully someone who knows the Gm300 tier radios will know the answer as my own detailed service manual seems to have walked away from me

I have a mate who is going to build me up a universal preamp to use on the audio output from a gm300 to make a balanced audio output at pro line level to feed into a pro audio mixer

His question to me was what level is the audio coming from pin 11 of the Gm300 ?

I tried myself with a dmm from pin 11 to gnd and tx'd on another radio to the rx radio but it showed nothing on the volts range

Anyone know the answer ?

Thank you in advance
Mike

mrtor wrote:I've been searching here on Batlabs and haven't come up with the answer so hopefully someone who knows the Gm300 tier radios will know the answer as my own detailed service manual seems to have walked away from me

I have a mate who is going to build me up a universal preamp to use on the audio output from a gm300 to make a balanced audio output at pro line level to feed into a pro audio mixer

His question to me was what level is the audio coming from pin 11 of the Gm300 ?

I tried myself with a dmm from pin 11 to gnd and tx'd on another radio to the rx radio but it showed nothing on the volts range

Anyone know the answer ?

Thank you in advance
Mike

My information indicates that pin 11 is a software programmable setting. You will probably have to use the radio software and set the output on pin 11 to squelched audio output. It will probably also have a DC bias on it, so you will want to use at least a 1.0 uf cap to isolate the DC voltage so you don't short it to ground with a transformer or what ever.

Jim

If I am correct pin 11 will be constant squelch noise. I normally run it thru a relay from COR (pin to close when carrier is detected and the audio goes to the amp. Most amps should handle the audio coming from here with no issues. We run it this way in many fire stations.

There is a three pin A B berg jumper in the radio to select the output on pin 11.
Pin 11 can have one of two Receiver audio outputs:
Filtered squelched audio at about 100 milivolts. This matches line in on most amps without any preamp needed.
Unfiltered discriminator audio.

Add a coupling capacitor for safety.

Will wrote:There is a three pin A B berg jumper in the radio to select the output on pin 11.
Pin 11 can have one of two Receiver audio outputs:
Filtered squelched audio at about 100 milivolts. This matches line in on most amps without any preamp needed.
Unfiltered discriminator audio.

Add a coupling capacitor for safety.

Thank you Will I knew someone would know, much appreciated

Cheers
Mike