on 11/13/02 8:35 PM, Dino Darling at k6rix@arrl.net wrote:
> Force 12 makes LPDAs! I had an e-mail exchange with Force 12 a while back
> and was told Force 12 would NEVER build LPDAs! The reasoning I got was
> that there is no advantage for the Amateur (I wanted it for Navy MARS) and
> that there were a few companies already making them. I was even pointed to
> Mr. Cebik to read about the performance of these antennas.
While an LPDA is a great antenna (I worked for Dr. Paul Mayes who was one of
the inventors of the beast), I do question it's usefulness in the amateur
world at HF.
An LPDA has less gain than a Yagi and while it has significantly broader
bandwidth, there's a lot of bandwidth covered that isn't particularly
necessary to the ham. As you pointed out those who also work in the MARS
bands will certainly find one more useful than a Yagi.
I know some beams like the CC X7 use an LPDA type arrangement for the driven
elements and that probably does help beamwidth.
But in an LPDA overall, most of the elements are not active at your
frequency of use.
I really don't know what one can get out of an LPDA that you cannot get out
of a well designed multi-band Yagi.
I'd love to be enlightened.
73,
Jon
NA9D
-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)
Citizen of the People's Democratic Republik of Illinois
Life Member: ARRL, NRA
Member: AMSAT, DXCC
http://www.qsl.net/na9d
"A life lived in fear is a life half lived."
|