Antenna questions...

[bob1234]

....here are your wierd questions of the week that are the result of
several bored people talking about building airplanes:

Can a thin foil tape be fastened to the front of a wooden spar to act
as a VHF antenna? The antenna would be encapsulated in several layers
of epoxy or spar varnish and would not be penetrated by rib nails
(wood ribs) or compression member bolts. The leading edge would be
composed of wood ply.

Can a steel wingtip bow in a rag and wood wing also be used as an
antenna?

Thanks,

Bob1234

[flybynightkarmarepair]

On Feb 9, 7:18*am, bob1234 > wrote:
> ...here are your wierd questions of the week that are the result of
> several bored people talking about building airplanes:
>
> Can a thin foil tape be fastened to the front of a wooden spar to act
> as a VHF antenna? *The antenna would be encapsulated in several layers
> of epoxy or spar varnish and would not be penetrated by rib nails
> (wood ribs) or compression member bolts. *The leading edge would be
> composed of wood ply.

Yes, in fact Jim Weir taught Bellanca how to do this on Vikings years
ago. You need a some RF baluns, but the composite antenna kit from
RST engineering has everything you need. You can do VOR antennas too.
>
> Can a steel wingtip bow in a rag and wood wing also be used as an
> antenna?

Probably not very well. It's oriented the wrong way, and tuning it
would be a PITA, if it's possible at all.
>
> Thanks,
>
> Bob1234

[RST Engineering[_2_]]

On Tue, 9 Feb 2010 07:18:59 -0800 (PST), bob1234
> wrote:

>...here are your wierd questions of the week that are the result of
>several bored people talking about building airplanes:
>
>Can a thin foil tape be fastened to the front of a wooden spar to act
>as a VHF antenna? The antenna would be encapsulated in several layers
>of epoxy or spar varnish and would not be penetrated by rib nails
>(wood ribs) or compression member bolts. The leading edge would be
>composed of wood ply.

We've been doing foil antennas in plastic airplanes for about thirty
years and it seems to work just fine. The only thing you want to
watch out for is keeping relatively large (either in area or length)
pieces of metal away from the outer halves of the antenna "ears".
Things like flying wires and control cables will drive it nuts.

You also need to feed a balanced dipole antenna with a balun (BALanced
to UNbalanced) between the antenna ears and the coax.

>
>Can a steel wingtip bow in a rag and wood wing also be used as an
>antenna?

Sort of. As an antenna for an FM radio it will work just fine.
However, as a tuned antenna, the odds of it being just the right
length are somewhere around the odds of winning an argument with an
FAA inspector.

Jim