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Old March 31st 08, 12:48 AM posted to rec.aviation.homebuilt
Sliker
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Default Metallic paint's effects on internal antennas

On Sat, 29 Mar 2008 12:17:48 -0400, "Peter Dohm"
wrote:

Hmm, that makes me wonder. I couldn't figure out why buried antennas
in places like the leading edge of vertical fins weren't getting as
good reception as an external antennas. Titanium dioxide in white. And
white is what the composite kitplane companies want us all to paint
our planes. I wonder where I can get some of that radome coating.....
:-) I always wondered why radomes looked a little different, or the
shade was off the rest of the plane. There must be something to the
paint, or they could just paint the radomes with the same paint as the
rest of the plane. Metal-flake is mylar?! that's the one thing I was
sure was little flakes of aluminum. No wonder it fades out over time
so bad. I can't see metal-flake on a plane though, that stuff is for
hot rods and dune buggies. If paint affects radomes, I wonder if radar
has different needs than just transmitting and recieving VHF radio
signals? And radar had changed so much also. Instead of the old 50,000
watt systems, they now do the same thing with 700 watts. I used to fly
a jet with the old 50,000 watt system, and the radar rotated all the
way around instead of sweeping back and forth. The airline told us a
special paint on the forward bulkhead stopped the beam from entering
the cockpit. But I used to worry about some flakes of it falling
off... Now that was one paint that definitely would stop all microwave
energy, and probably any other radio energy. The problem is if I go to
the paint store and buy a gallon of Imron Pewter Metalic, the can
really doesn't say what makes up the metallic effect of the paint.
Possibly Dupont could supply this info.


For the last 25 years or so, a lot of paint that looks metalic is not and a
lot of paint that looks non metalic is--and I am actually wrong to even call
most of it paint. Most metal-flake is/was mylar and white paint is titanium
dioxide--which is why "white covers black or your money back".

In any case, I have been away from that sort of thing too long and don't
even know whether you may need a "radome coating"; but any good aircraft
paint shop or aircraft paint distributor should know and a lot of avionics
shops that work on major retrofits should know as well.

Best of luck, and please let us all know what you find out.

Peter