On Sun, 31 Oct 2004 17:50:28 -0800, "Carl J. Hixon"
wrote:


By the numbers:
(1) So how do I calculate lengths for other frequencies? ie 121.5MHz,
146.73MHZ, 123.0 MHz
By the proportion to the original frequency (this is called scalable).
This usually implies thickness too,

Thank you for the reply. Care to show me an example? I don't know which
lenghts are important, do I scale the radiator lenght, distance between
radiator and shorting stub, and / or shorting stub?

(3) Where can I finde a descent but cheap SWR meter?
Radio Shack.

I had checked at my local radio shack and the kid had no idea what I was
talking about. Walked around and said, "we must not have them." It's not a
very good store...only good at selling their toys, phones, etc. The Shack
isn't what it used to be. Can anybody recommend a brand / model for under
$100?

Thanks,
Carl

Carl,
I know that this isn't the answer you are seeking but I'll give it a
go anyway. Whay not just use a quarter wave? If your ultralight
aircraft has a metal framework and/or skin you could use that as the
'missing half' and just use a 1/4 wave whip. This is done in land
mobile all the time, a 1/4 wave whip that uses the vehicle body as the
ground plane. While I might be missing something by not knowing much
of anything about the aircraft you wish to mount this on it seems like
the simplest solution. I've built 3 from published measurements and
the SWR was acceptable on all (under 1.5:1) without pruning. Figure
the center frequency of where you plan to operate (on each band) cut
for that and call it a day. If you do wish to get the SWR meter
anyway another poster recommeded a Daiwa - I have one of their SWR
meters and concurr with his recommendation.
Howard