Metallic paint's effects on internal antennas

"Sliker" wrote in message
...
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.


DuPont is an excellent source, and will also be able to point you to a
distributor for their aviation products.

The only thing that I remember about the radome paint/coating is that it was
very slightly conductive--even at the surface. But the bulkhead was another
matter, since the metal bulkhead was a pretty good barrier in its own right
and I believe that there was a fairly substantial energy absorbing blanket
ahead of the bulkhead for those old C-band Sperry radars. Purely as an
aside, I have no idea why they continued to only display 90 degrees of arc
long after larger and brighter displays could have easily provided a
reliable display of more than 200 degrees--since the only limitation would
have been blanketing by the engines and wing tips.

Peter
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