[Antennas] Best guess on adjusting a 80 down to 75

[Chris Boone]

Current freq x length = constant....that / divided by wanted freq will give
you overall length to trim to...

Chris
WB5ITT 

-----Original Message-----
From: Antennas [mailto:antennas-bounces at mailman.qth.net] On Behalf Of Ray
Brown
Sent: Wednesday, September 16, 2015 9:34 PM
To: ANTENNAS-Mailman
Subject: [Antennas] Best guess on adjusting a 80 down to 75


  Greetings, all.. I bought and tossed up a 80 / 40 dipole in my back yard,
in a NVIS fashion, so that I can work stations within a couple hundred
miles.
The problem is that the measured SWR on both antennas are at the top of the
CW band, and I want to go in the middle of the phone band. My radio doesn't
like greater than 3:1 SWR for some reason.

  Now, I'm not going to cut the copper. Just double it back tight so that it
doesn't cause any arcing or corona. (Only running 100w, but just to be
safe.)

  So... all other things being equal, using the best scientific guessing,
how much would I need to move the eggs, the insulators, back to get to the
middle of the phone bands on this 80 / 40? I'd really like to do this just
once if possible.

  Thanks!


                Ray, KB0STN










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