Com1 activating Com2 squelch

**Sue Bon** · April 30, 2023

Hi guys,

I'm back after a long and frustrating panel upgrade. I'm super stoked with 99% but I'm dealing with one issue... If I have Com1 and Com2 audio active (using Com1, monitoring Com2 on 121.5), when I speak on Com1 it activates the squelch of Com2 causing lots of static feedback in my headset. ATC doesn't hear it, but it's brutal on my side. I see the RX on Com2, so that's how I know it's being activated.

Here's another thing... it's not all the time. It happens maybe 75% of the time, but not every single time.

Any thoughts?

I'm loving the GFC500 and the GTN650Xi.

Maybe it helps to know that my Com1 is now GTN650Xi and Com2 is my old GNS 430W.

Can't wait to hear your thoughts

Sue

**N201MKTurbo** · April 30, 2023

Does it happen on all transmit frequencies? Or just some?

Your avionics shop needs to double check the coax makeup and radio grounding. If all checks OK, have them check the VSWR of both antennas from the radio connectors. If they can’t cure the bleed over with antenna work, you should have them adjust the squelch on the receiver.

**RoundTwo** · April 30, 2023

Hopefully they updated the antenna cable with a modern dual-shield like RG-400 instead of using the old RG-58 that is who knows how old.

**Ragsf15e** · April 30, 2023

2 hours ago, Sue Bon said:

Hi guys,

I'm back after a long and frustrating panel upgrade. I'm super stoked with 99% but I'm dealing with one issue... If I have Com1 and Com2 audio active (using Com1, monitoring Com2 on 121.5), when I speak on Com1 it activates the squelch of Com2 causing lots of static feedback in my headset. ATC doesn't hear it, but it's brutal on my side. I see the RX on Com2, so that's how I know it's being activated.

Here's another thing... it's not all the time. It happens maybe 75% of the time, but not every single time.

Any thoughts?

I'm loving the GFC500 and the GTN650Xi.

Maybe it helps to know that my Com1 is now GTN650Xi and Com2 is my old GNS 430W.

Can't wait to hear your thoughts

Sue

As @N201MKTurbo said, there are a couple more in depth things that should be checked first, but the squelch is adjustable if the radios were properly set up and grounded. Others have had issues where they needed to lower the squelch from standard on their 650, so I wonder if the shop played with it?

Also, are your antennas top/bottom? If they’re on the same side, how close?

**Sue Bon** · May 1, 2023

9 hours ago, N201MKTurbo said:

Does it happen on all transmit frequencies? Or just some?

Hmm... Maybe this is why it doesn't happen all the time. Maybe it's something to do with the frequencies.

He did adjust the squelch on the receiver, but didn't want to turn it down too much.

9 hours ago, RoundTwo said:

Hopefully they updated the antenna cable with a modern dual-shield like RG-400 instead of using the old RG-58 that is who knows how old.

He did say new cables. My invoice says Coaxial cable RG-142. Is that it? I also have a Coaxial cable P/N GX03272.