Today's Message Index:
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1. 06:13 AM - Re: Re: Troubleshooting radio whine/noise on C essna 182P (Jan)
2. 06:52 AM - Re: Rotax ignition wiring (user9253)
3. 06:52 AM - Re: Troubleshooting radio whine/noise on C essna 182P (user9253)
Message 1
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| Subject: | Re: Troubleshooting radio whine/noise on C essna |
182P
Will be interesting to hear what the final outcome will be on your "noise" problem.
Regarding the isolation of the microphone - I am sure someone can give a better
technical answer than I can. Simply put I think of the microphone circuit as
being electrically insulated from chassis ground - hence you need too run two
separate wires back to your radio. Think of it this way ... The microphone receives
a steady signal on one wire - you speak into the mic - that changes the
signal which now go back to the radio in the other wire ... :-)
The shield you have on the wire is to prevent any changes to the signal in the
two wires ...
All the best
Jan
> On Nov 26, 2015, at 01:38, sacha <uuccio@gmail.com> wrote:
>
>
> Jan,
>
> I think at this point I would agree with you: the problem is most likely related
to the voltage regulator, not to switches.
>
> I have ascertained that the noise is entering through the wires, not the antenna
as its volume is independent of the radio volume.
>
> I also tested the noise suppressor capacitor (cessna part 0770038-2) today with
a multi-meter but I could not get it to give a reading so it may be fried.
Although I just realized that I did not make sure it was discharged before I
attempted to take the reading. I'll have to take that reading again. Nevertheless,
the look of the part (an old rusty box), age of the plane (43yrs young)
and the fact that I have seen capacitors fail in other equipment makes me think
this might be a good candidate for replacement.
>
> Regarding insulation of mic/headphone jacks, is it correct that mic jacks must
be insulated from the airframe, but the headphone jacks may either be grounded
to the airframe or insulated with a separate ground wire running back to the
intercom? If it is correct, can someone explain the logic?
>
> Happy Thanksgiving
> Sacha
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=450304#450304
>
>
>
>
>
>
>
>
>
>
Message 2
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| Subject: | Re: Rotax ignition wiring |
Happy Thanksgiving !
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=450310#450310
Message 3
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| Subject: | Re: Troubleshooting radio whine/noise on C essna 182P |
The microphone jack should definitely not be grounded locally to the airframe,
because other varying current (noise) through the airframe will get amplified
along with the microphone signal. It is good practice not to ground the headphone
jack either.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=450311#450311
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