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Why does the Audio Cut out.....
- Thread starter Eastside
- Start date
It's just the way they are designed. Older rigs used relays to key the radio, these are done electronically. I cannot explain to you why they did them this way, since Galaxy is keyed electronically, but you can disconnect the mic andd still receive. Maybe it's the same goober engineer that put 5 pin mics on the Cobra's and Uniden's!
73,
RT307
73,
RT307
The mic plug acts as a 'switch' in the audio/speaker wiring. If the mic isn't connected, that audio line is 'open' and the speaker is disconnected. I have no idea why it's done that way, but it is and has been for quite some time. Seems senseless to me.
- 'Doc
- 'Doc
Sure - figure out which terminals the mike connects when it's plugged in and install a short jumper inside the radio that serves the same purpose.
Do this at your own risk, however.
Do this at your own risk, however.
If I take a wire and ground 1 of the prongs to the case...the audio comes on.
The reason I want to mod the radios to stay on with the mic unplugged is so they will work with my rack gear.....my plug from my mixer is 4 pin cobra on the radio end and ph jack on the mixer end.....it keys the radios but the audio does not come on.
Why do you have the need to change it? Howabout just be aware of it and act accordingly? It's no big dealio.
The Uniden/Cobra radios that have that feature work well with mics equipped with built-in talkback.
Been there; done that.
Just don't fry that radio!
The Uniden/Cobra radios that have that feature work well with mics equipped with built-in talkback.
Been there; done that.
Just don't fry that radio!
Read my post #7.
If you are using an aftermarket/high end mic and a preamp; then wiring these CORRECTLY should work the same as a stock mic would.
IOW - this shouldn't be an issue if it was done correctly.
Perhaps your wiring isn't correct then - eh?
Something is different...with the Uniden PC76 and the 148gtl.....because my cable from my mixer works with all my other 4 pin radios....my Texas Ranger 966ffc and my Galaxy etc.....it will key up and transmit the pc76 and the 148....just no audio?
Pleeez elaborate.
Just as the earlier posts have stated, the switch inside the microphone completes the audio circuit to the speaker when in receive.
during transmit the switch opens the receive circuit and closes the transmit circuit.
Sure you can ground pin 4 (rx) and have receive audio without a microphone plugged in BUT the drawback is that when you transmit the receive circuit is still closed.
This results in wide open talkback or one BIG squeal.
most older radios relied on the key switch in the mic to do the tx/rx switching, in the newer radios like your TR & galaxy this isnt the case and it is why they work when your 76 and 148 don't.
also in the older radios when people wanted talkback to monitor toys or echo they would install a resistor between the speaker ground and chassis ground.
The more resistance, the less talkback.
if you short mic pin 4/speaker ground to ground... and transmit you will have wide open talkback.
try it for yourself, you wont hurt anything... except maybe your ear drums
there are a couple of ways that you could bypass this so that your rack gear would work with the 148 and 76.
the easiest solution that comes to mind would be to use a miniature relay, NC on the wire going to pin 4. ground the coil of the relay to the chassis ground and feed the other side of the coil with +8v TX which can be found in several places in the cb.
this would let the 76 & 148 work with your rack gear and still work with their microphones
Just as the earlier posts have stated, the switch inside the microphone completes the audio circuit to the speaker when in receive.
during transmit the switch opens the receive circuit and closes the transmit circuit.
Sure you can ground pin 4 (rx) and have receive audio without a microphone plugged in BUT the drawback is that when you transmit the receive circuit is still closed.
This results in wide open talkback or one BIG squeal.
most older radios relied on the key switch in the mic to do the tx/rx switching, in the newer radios like your TR & galaxy this isnt the case and it is why they work when your 76 and 148 don't.
also in the older radios when people wanted talkback to monitor toys or echo they would install a resistor between the speaker ground and chassis ground.
The more resistance, the less talkback.
if you short mic pin 4/speaker ground to ground... and transmit you will have wide open talkback.
try it for yourself, you wont hurt anything... except maybe your ear drums
there are a couple of ways that you could bypass this so that your rack gear would work with the 148 and 76.
the easiest solution that comes to mind would be to use a miniature relay, NC on the wire going to pin 4. ground the coil of the relay to the chassis ground and feed the other side of the coil with +8v TX which can be found in several places in the cb.
this would let the 76 & 148 work with your rack gear and still work with their microphones
Thanks for explaining that...I really appreciate it....also thanks for the mod....A lot of guys are doing the hifi mod to those 2 radios and usng rack gear....I wonder if that is how they are getting around it...I have not seen any other threads mention this?