Squelch breaking on SL40

[FORANE]

I have a Garmin SL40 comm 1 and a Garmin 430W as comm2. For as long as it has been in the plane, the SL40 would frequently break squelch. It seems to occur on random frequencies. It may be immediately stopped by changing to a different (non occurring) frequency, and will immediately return on the original frequency or various other frequencies which it happens on.

I got fed up with it today and started pulling breakers in flight. Turns out the squelch break on the SL40 immediately and completely goes away when the 430W is powered off.

The 430W gps antenna is located in close proximity to the SL40 antenna; not sure if that may be relevant...

Where should I look to narrow down the cause?

 

[flyingron]

I'd check grounding first. You can adjust the fixed squelch on the 40 in the setup menu. I don't have my books handy but you do something like hold SYS and <> down at the same time while you turn on the radio. Cycling through the menus gets you to the squelch setting.

 

[FORANE]

I'd check grounding first. You can adjust the fixed squelch on the 40 in the setup menu. I don't have my books handy but you do something like hold SYS and <> down at the same time while you turn on the radio. Cycling through the menus gets you to the squelch setting.

Yes, I have tried adjusting the squelch before. Shouldn't get better with the 430W off though unless there is some sort of issue. Maybe one of the comms does have a bad ground.

 

[kgruber]

Sometimes two COMs are connected by a wire.