Thanks to everyone for the help/tips/theory on my 40m & up
antenna project. It's working fb now.

Note: the 1.6:1 minimum SWR I was seeing went away after
the sun dried off the roof and feedline. Now I get a 1.1:1 or
better match. Still can't get a decent match on 12m. On 10m
my autotuner (Elecraft KAT2 internal) has to work hard to get
a match. It's not my only antenna for the upper bands so I'm
not too concerned.

Ken
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Just my 2¢... 73 es gd dx de Ken KGØWX
Grid EM17ip, Flying Pigs #-1055
Proud builder & owner of Elecraft K2 #4913

On Fri, 29 Jul 2005 03:44:50 GMT, KU2S wrote:


You're looking at MAYBE a three percent improvement in signal. As the
others have said, it's not broken, so why fix it?

If I understood Ken's configuration on 7MHz, on my modelling adding
about 14' to the ladder line would reduce the losses in the RG58 by
about 1.5dB, which is a 40% increase in EIRP. Of course, that
addresses performance on 40m only.

That is a lot more than the unsubstantiated "MAYBE a few percent".

It is up to Ken if he wants to chase 40%... perhaps that is why he
asked the question in the first place. He might have an interest in
understanding and learning, he might be one of the remaining folk who
think that ham radio is "for the purpose of self-training,
intercommunication and technical investigations" (from ITU RR 1.56).

One might think from Ken's first posting that he wants this antenna
for 40m solely, but then he expressed disappointment with being unable
to match up on 24MHz, so that creates some suspicion that he may be
looking for a multi band or all band antenna.

Ken, if you can't match up on high bands, it is a warning that the
impedance is outside the tuner's capacity, and probably outside good
performance. Similarly, if the tuner does deliver low SWR but is very
sharp in tuning, it is an indication that the "loaded Q" of the tuner
is high and probably excessively lossy. Beware of matching an unknown
antenna and being satisfied that it is good so long as you can "get
the SWR down".

Owen
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