Date: Sun, 25 Mar 2018 15:39:53 -0700
From: "Richard (Rick) Karlquist" <richard@karlquist.com>
To: jim@audiosystemsgroup.com, towertalk@contesting.com
Subject: Re: [TowerTalk] XM240 SWR plots
< When I first got my MonstIR up, I took
advantage of the fact that I could adjust the length of the three
elements individually. Just to prove a point, I tuned up the antenna
the usual way for CW (all 3 elements optimized); then I QSYed the
radio to the phone band. The SWR was not ridiculously high and a
radio with a tuner could drive it. I retuned just the driven element to
get the best SWR I could, without changing the parasitic elements.
That improved the SWR somewhat. However, as expected, the antenna
suffered a substantial drop in gain and F/B ratio to where it wasn't
much better than a rotatable dipole.
Rick N6RK
## IF you had left all 3 els alone... and just say used a tuner, did the FB /
FR /gain drop off at upper end of band ?
When I see typ plots of 3 el yagis, tuned for the lower part of the band, the
gain actually increases a tiny bit towards
the top of the band.... meanwhile ..at top of band, the swr and FB / FS go
straight to hell..quick like.
Jim VE7RF
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