Metallic paint and composite antenna signal strength

What about metal flake paint?

On Fri, 24 Jun 2005 08:56:02 -0700, "RST Engineering"
wrote:


"firstflight" wrote in message
...

Will a metallic paint interfere with the strength of signal with impeded
antennas

What is an impeded antenna?



in a composite airplane?

I ran some tests with both nav, com, dme, and transponder antennas imbedded
in the wing of a Bellanca aircraft under controlled test conditions at the
Bellanca factory back in the 1970s. The wing was wood with fabric covering.
The fabric had the standard silver (aluminum) UV dope over the fabric and
then polyurethane paint over the dope.

We measured (both ground and airborne) the signal strength from both the
standard antenna on the exterior of the aircraft and the ones imbedded in
the wings and found no degradation of signal strength from the imbedded
antennas from the reference antennas mounted on the fuselage.

Does this mean that you can't go out there and find some paint that will
screw up the reception? No. What it means is that we DID try it with one
form of metallic paint and there were no effects. Certainly you would think
that out of ten thousand internal plastic plane antennas we've sold over the
last thirty years we would have had at least ONE complaint from metallic
paint problems. We haven't. You may be the first. That's why we paint
EXPERIMENTAL on the sides of our aircraft.



I have a small transponder antenna and a
Comm antenna bonded to the inside of the fuselage.

Why on earth would you bond a transponder antenna to the inside of the
fuselage? How do you get lower hemispherical (not biconical) radiation from
something bonded to the fuselage?

Jim

What about it?

Jim


"Joe Camp" wrote in message
...

What about metal flake paint?

On Sat, 25 Jun 2005 09:14:08 -0700, "RST Engineering"
wrote:

What about it?

Jim


"Joe Camp" wrote in message
.. .

What about metal flake paint?

Metal flake paint has considerably more metal, and bigger pieces of
it. Wouldn't that block the signal to and from an embedded antenna?

I have absolutely no idea. I can tell you how to run a test on it if you
would like.

Jim



Joe Camp wrote in message
...
On Sat, 25 Jun 2005 09:14:08 -0700, "RST Engineering"
wrote:

What about it?

Jim


"Joe Camp" wrote in message
. ..

What about metal flake paint?

Metal flake paint has considerably more metal, and bigger pieces of
it. Wouldn't that block the signal to and from an embedded antenna?

"RST Engineering" wrote:

I have absolutely no idea. I can tell you how to run a test on it if you
would like.

Had a customer paint his pager case with metalflake paint - didn't
work worth squat when he was done. I suspect the effect would be the
same on any radome (since that's what a pager case is).

Mark "but it was sporty lookin' " Hickey

Joe Camp wrote in message
.. .
On Sat, 25 Jun 2005 09:14:08 -0700, "RST Engineering"
wrote:

What about it?

Jim


"Joe Camp" wrote in message
...

What about metal flake paint?

Metal flake paint has considerably more metal, and bigger pieces of
it. Wouldn't that block the signal to and from an embedded antenna?

Mark ...

I mean no offense, but anecdotal evidence about painting pagers doesn't take
the place of a controlled environment test when it comes to making general
pronouncements about antennas inside of one paint or the other.

So far as I know, the paint could have leaked inside, the pager could have
crapped out from natural causes...

Jim


"Mark Hickey" wrote in message
...
"RST Engineering" wrote:

I have absolutely no idea. I can tell you how to run a test on it if you
would like.

Had a customer paint his pager case with metalflake paint - didn't
work worth squat when he was done. I suspect the effect would be the
same on any radome (since that's what a pager case is).

RST Engineering wrote:

Mark ...

I mean no offense, but anecdotal evidence about painting pagers doesn't take
the place of a controlled environment test when it comes to making general
pronouncements about antennas inside of one paint or the other.

So far as I know, the paint could have leaked inside, the pager could have
crapped out from natural causes...

They also operate in all the normal bands...
VHF Low/Hi, UHF, 800/900/1200 mhz and probably more...

"RST Engineering" wrote:

Mark ...

I mean no offense, but anecdotal evidence about painting pagers doesn't take
the place of a controlled environment test when it comes to making general
pronouncements about antennas inside of one paint or the other.

Of course not, but the fact the paint DID affect the operation of the
pager shows that there WILL be an effect on the operation of the
antenna inside the painted radome. The controlled environmental
testing will determine the magnitude. Kinda like giving a dose of a
substance to a mouse. It squeaks, drops dead quivering ten seconds
later... it would be safe to say the substance wouldn't be good to
ingest, but you'd have to do more testing to find out just how
dangerous it is.

So far as I know, the paint could have leaked inside, the pager could have
crapped out from natural causes...

Nope - with a new pager case, the thing worked like new. And FWIW,
the testing of the pager did involve a radiation test fixture inside a
Lindgren screen room, and lotsa nice HP test equipment.

Mark "wouldn't have brought it up otherwise" Hickey

Jim


"Mark Hickey" wrote in message
.. .
"RST Engineering" wrote:

I have absolutely no idea. I can tell you how to run a test on it if you
would like.

Had a customer paint his pager case with metalflake paint - didn't
work worth squat when he was done. I suspect the effect would be the
same on any radome (since that's what a pager case is).

"Joe Camp" wrote in message
.. .

What about metal flake paint?

Metal flake paint has considerably more metal, and bigger pieces of
it. Wouldn't that block the signal to and from an embedded antenna?

I'm sorry to but in this late in the thread, and further since I have been
away from avionics for 20 years...and was almost exclusively a Comm
and VOR technicial at the time.

But I'm not sure that all metal-flake paint has any metal it it. As I
recall, a lot of is is/was "mylar". Back when I was last involved,
metal-flake was enjoying a resurgence of popularity (after a 15 to
20 year slump) and we were seeing King Air 200's with metal-
flake radome paint--which contained a small amount of added
conductive material, just like the plain radome paint...

Your local DuPont supplier of aircraft paint should be a good
information source. They have an outstanding product line and
are/were quite helpfull.

Peter