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Re: [TowerTalk] 80 meter dipole

To: Tom Osborne <w7why@frontier.com>
Subject: Re: [TowerTalk] 80 meter dipole
From: Dan Hearn <n5ardxcc@gmail.com>
Date: Sun, 20 Jul 2014 19:12:51 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Tom: How high is your dipole? Unless it is well over 1/2 wavelength, the
feed point impedance is probably around 25 ohms. You are feeding it with 75
ohm coax, a bad mismatch. Do you have a line choke at the feed point? If
not, your coax outer shield is probably radiating as part of the antenna.
Sounds like you might need to redesign the antenna.

73, Dan, N5AR



On Sun, Jul 20, 2014 at 5:36 PM, Tom Osborne <w7why@frontier.com> wrote:

> I recently put up a dipole for 80 and used some RG-6 CATV coax to feed it.
>  Good news is that I cut it for 3550 and the SWR is about 1.3:1 there.  Bad
> news is that it stays pretty much the same all the way up the band.
>
> Is the wide bandwildth because the coax is so lossy?  It is the double
> shielded stuff with 2-layers of foil and 1-layer of braid. 73
> Tom W7WHY
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-- 
Dan Hearn
N5AR
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