On 06/16/2013 09:52 PM, Remi Guerner wrote:
>
> Frans,
> I have made some more investigations before reading your message. Here are the
results:
> 1. Charging my iPad with my charger in another aircraft (Dyn Aero MCR 01): no
noise.
> 2. Charging my iPad with a friend's charger in my aircraft: same noise as with
my own charger.
> So it seems that the problem comes from the configuration of my panel and
> wiring:
my cigar lighter is located very close to the Com radio while in the MCR
is located very far on the passenger side.
You see what some testing can reveal! Now it looks like it has something
to do with the wiring in your specific panel. Maybe the wiring has a
specific length which "resonates" at comm frequency and thus acts like
an antenna, or causing the oscillator in the charger to move its
frequency slightly so it ends up in the comm frequency band.
I'm now confident that you can solve the problem. Have you tried to
solder a capacitor over the two wires of the cigar lighter plug?
Or wrap the cigar lighter plug wires around a ferrite core (or better
yet, through a torroid?)
You may have noticed that today many cords of chargers and power
supplies have a thick cylinder inside the cord, most often close to the
device it is supposed to charge. Inside this cylinder there is such a
torroid and it is there just to avoid the problems you describe. So,
obtain such a cord from an old laptop power supply, trim it to length
(leaving the cylinder where it is) and use this cord to feed your cigar
lighter. I it also a good idea to use such a cord to feed your radio
(just make sure the wire diameter is up to spec).
Let's first try these simple solutions. I suspect that it will solve
your problem. Otherwise I know a few more but I don't think it will be
necessary.
Frans
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