strobe:comm radio noise

[offpiste]

While in flight last week, my radio suddenly began spewing out a powerful white noise. After a bit of switch flipping, it turned out to be the strobe causing the static. A quick examination of wiring showed nothing unusual...

Any advice or ideas on what could cause this will be most welcome! Thanks to all! Bob

[zero.one.victor]

Here's another one: my buddy installed (slid-in) a Narco 11B com radio,which he happened to buy from our very own Blue Leader. It was in good working order when removed, according to BL. After installation, the automatic squelch wouldn't squelch. So anytime that nobody was transmitting on the frequency, it would hiss. Very annoying.
We were flying somewhere together a few days ago when my buddy told me over the radio that he'd been having trouble with his stall warning buzzer, the switch out on the wing apparently was sticky or had an intermittant short. So now it was buzzing away merrily while at cruise speed. In between that & the hissy fit the radio was having, he was going nuts. I advised him to just pull the circuit breaker for the stall horn, til he could diagnose & fix the problem.
Lo & behold, the hiss from the radio went away! So now, besides fixing the stall switch, he's gotta trace out the wiring from that CB & see where it ties into the radio wiring so he can disconnect it.

Eric

[mvivion]

The strobe power pack should have a separate wire to ground to prevent this. that said, some strobes can be a real pain in the ears, if mounted too close to strategic wiring.

If this just started, I'd take another close look at the strobe power pack, and look for a very fine wire, hanging around there somewhere, as in loose.

Mike V

[GAHorn]

I don't knowt that this suggestion applies to this particular thread's difficulty...but it occurs to me to mention a thing about grounds.
The strobe lamps have a shielded cable in their power supply line. That shielding should ONLY be grounded at the power supply to the airframe. Do NOT ground it at both ends or you'll create a "ground loop" which can/will cause all sorts of gremlins to appear. Same is true of most shielded wires....unless they are specifically designed to be grounded at both ends (such as spark plug leads)....ground them at one end only.

[johneeb]

George,

I am going to check all of my ground wire shields to make sure none of them are grounded at both ends. I have ridden through a couple of "ground loops" and do not want to that again.

Johneb