Squelch Jump

Noticed recently that I had to crank the squelch on my radio much higher. Radio is a panel-mounted Icom IC-A5.

Flown for years at the previous squelch setting (8, if I remember correctly). Had a lot of squelch breaking for no reason on the last flight. Today it was continuous, and didn't go away until I cranked it up to 14 (16 is max).

Any idea why this would happen suddenly? The noise doesn't seem to be related to the ignition unless there's a common failure point between the two mags; there's no change with a mag check.

The antenna is a whip mounted below a wooden panel, with a 12x18" sheet of aluminum foil as a grounding plane. It's about a six-foot coax run to the radio.

Only thing that comes to mind, maybe, is the sheld side of the coax got somehow compromised.

Any other ideas?

Ron Wanttaja

Ron,

Your friendly neighborhood radio tech will tell you that your radio has maybe two internal squelch controls in it. In my radio, a King KY-197, the first is set for the signal level, the second for the level of the audio on the signal. You just need the internal squelch adjusted. I will hazard a guess that vibration and age have affected a component or two.

Best of luck,

Wes
N78PS

It could be something like an alternator capacitor gone south or the wire to the alternator capacitor broken.....

Also with portable hand held radio installs, a broken/frayed shield on the mic/headset/ptt lines is always a concern...

If you have a Cessna the Capacitor is expensive, if you have an experimental it is just a few bucks at the local
automotive emporium.

Quote:

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Originally Posted by rwanttaja

Noticed recently that I had to crank the squelch on my radio much higher. Radio is a panel-mounted Icom IC-A5.

Flown for years at the previous squelch setting (8, if I remember correctly). Had a lot of squelch breaking for no reason on the last flight. Today it was continuous, and didn't go away until I cranked it up to 14 (16 is max).

Any idea why this would happen suddenly? The noise doesn't seem to be related to the ignition unless there's a common failure point between the two mags; there's no change with a mag check.

The antenna is a whip mounted below a wooden panel, with a 12x18" sheet of aluminum foil as a grounding plane. It's about a six-foot coax run to the radio.

Only thing that comes to mind, maybe, is the sheld side of the coax got somehow compromised.

Any other ideas?

Ron Wanttaja

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Cheap stuff first.
See if wrapping the mike with a bit of cloth helps.
Make sure your mike is facing the correct way if the mike is on a flex boom...
Change headsets and see if the problem persists.

Chris

Quote:

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Originally Posted by Hiperbiper

Cheap stuff first.
See if wrapping the mike with a bit of cloth helps.
Make sure your mike is facing the correct way if the mike is on a flex boom...
Change headsets and see if the problem persists.

Chris

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The problem is the squelch level on the receiver, positioning of the mike doesn't matter.

Thanks for the suggestions everyone...I'm going to examine the shielding. I rebuilt the electrical system earlier this year, and though it worked fine for several months afterward, I wonder if something got disturbed.

Ron Wanttaja