The antenna of AC7JF?
J. Mc Laughlin
A long time colleague of mine, who was once my student and is now retired,
is also a great fan of antennas. While driving around Lake Havasu City, AZ,
looking at antennas - do we not all do that when we travel - he spotted (and
photographed) the antenna of AC7JF.
The antenna can be seen at: docpg.org
The antenna appears to have four, yagi style elements, to be feeding one
element with a second element connected to the driven element with a
transposed TL, and appears to be using stubs on the ends of the elements to
effect tri-band performance.
Hy-Gain uses a similar scheme on one of their verticals.
I think that I have seen this antenna before, but I can no longer place it.
Any suggestions?
73, Mac N8TT
--
J. McLaughlin; Michigan, USA
Home: J...@power-net.net
tom
It's a bit hard to see, but it looks like the feed (left to right in the
picture) is to the 2nd element with a crossed phase parallel line to the
third.
tom
K0TAR
Ralph Mowery
"J. Mc Laughlin" <j...@power-net.net> wrote in message
news:48idnR8BXqaoRZTW...@bright.net...
Probably this one:
http://www.hamanuals.com/MMans/KLM80.pdf
A KLM-34A.
I am not sure why they went out of business, but they seemed to make good
antennas. I have the OSCAR combination of the 2 meter and 432 mhz system.
J. Mc Laughlin
Spot on! Thanks.
Complicated antenna. Would be a big challenge to model.
73, Mac N8TT
--
J. McLaughlin; Michigan, USA
Home: J...@power-net.net
"Ralph Mowery" <rmower...@earthlink.net> wrote in message
news:aeSdncA3j_gbYJTW...@earthlink.com...
Jeff Liebermann
<rmower...@earthlink.net> wrote:
>Probably this one:
>http://www.hamanuals.com/MMans/KLM80.pdf
>
>A KLM-34A.
>
>I am not sure why they went out of business, but they seemed to make good
>antennas. I have the OSCAR combination of the 2 meter and 432 mhz system.
This might explain some of it:
<http://www.qsl.net/wb6jnn/middle.htm>
"Unfortunately, the Ham Radio business isn't as lucrative as most hams
think it is, especially for a U.S. based manufacturer. While Japanese
companies have all of their million plus ham market plus Europe plus
the U.S., we had only the domestic market which at that time was not
in a growth mode. KLM was sold to a new owner in 1979. It later sold
again and ultimately adopted the Mirage label for its amplifier line
(based on Ken Holladay's designs, originally) and has since then split
up to seperate owners for the antenna and amplifier businesses. The
KLM antenna line, in fact, disappeared abruptly late in 1999."
--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Jeff Liebermann
<rmower...@earthlink.net> wrote:
>"J. Mc Laughlin" <j...@power-net.net> wrote in message
>news:48idnR8BXqaoRZTW...@bright.net...
>> The antenna can be seen at: http://docpg.org
>Probably this one:
>http://www.hamanuals.com/MMans/KLM80.pdf
>
>A KLM-34A.
Yep. The photo looks like the original by KLM known as the KT-34. The
shorting bars are heavier (thicker) on the version currently made by
M2, known as the KT-34M2. See:
<http://www.m2inc.com>
<http://www.m2inc.com/products/kt/kt34/kt34m2.html>
<http://www.m2inc.com/products/klmaddon/index.html>
Better photos:
<http://n4zi.net/kt34xa_upgrade_page.htm>
Mike Staal (W6MYC), one of the founders of KLM, runs M2
<http://www.cq-vhf.com/M2AntennaFall06.html>
and might offer some assistance.
Doing a bit more Googling, I found plenty of detail at:
<http://lists.contesting.com/archives//html/towertalk/2008-04/msg00135.html>
<http://lists.contesting.com/archives//html/Towertalk/2008-03/msg00478.html>
which indicates that a model may be a challenge:
> For entertainment, and with low expectations, I put together a model of
> the KT34A using MMANA, recognizing that, for free, you cannot get high
> quality results. I can supply the input file if anyone is interested.
> M2 indicates that more sophisticated models are need to handle the novel
> loading. Using capacitive loads in the model for the two traps, I
> experimented with values of capacitance that would produce resonances
> that were either my observed ones or M2 measured ones for the individual
> elements. Somewhat surprisingly, the required Cs are not terribly
> different from what you get by calculation for a co-cylinder cap of the
> actual dimensions. Note that the inductances for the traps are
> determined by the dimensions of the loops in the elements and these are
> probably modeled okay. The model has all the segments of the actual
> antenna, aside from capacitors.
(etc...)