>--> RV-List message posted by: Joe Czachorowski <midnight@UDel.Edu>
>
> I have a small annoying problem. I have a King KY97A Comm
>radio. It was pre-wired at the factory (I guess). It works great as
>long as the electric turn coordinator is not running. When I hook up
>the turn coordinator, I get the motor(gyro?) noise in my headset with
>the squelch off. If I turn the squelch on, I don't hear it. I'm doing
>this test with the engine NOT running. Is this normal? Will this noise
>also affect my transmissions? BTW, I have individual ground wires going
>to a common ground block on the firewall as per Electric Bob. Any ideas
>out there?
>
Turn coordinators are high on the list of potential
noise generators. What you describe is consistent with
noise conducted out of the TC and onto the bus via its
14v power lead. Try putting a filter in the leadwires
to the TC. Radio Shack has an inductor, capacitor combo they
sell for about $4. It will need to mount in a small "project
box". I generally wire up the components with a pair of
goesinta and goesouta wires through grommets. The RS
part number for electrical components kit is 270-030.
I've published a copy of a drawing describing a power
conditioner we used to build at:
http://www.aeroelectric.com/errata/pwr_cnd.pdf
which you are welcome to download and use for guidance
on fabrication of your own noise filter.
Bob . . .
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