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Re: [TowerTalk] 43ft Vertical Feeding Question and Balun type

To: "Terry Conboy" <>,
Subject: Re: [TowerTalk] 43ft Vertical Feeding Question and Balun type
From: "Dan Zimmerman N3OX" <>
Date: Thu, 20 Nov 2008 22:34:28 -0500
List-post: <">>
> Perhaps there is a question of semantics to say that a 0.08
> wavelength vertical, which has about a 2.5 ohm radiation resistance,
> qualifies as a "fairly good" antenna on 160m?

Semantics and expectations.  I tried a 40 foot base loaded wire vertical on
160m and thought it was terrible because I could only just barely work DF2PY
and S59A with 100W.    I knew they were some of the big guns, so if I had to
struggle to work them, I wasn't going to get much 160m DXing done with that
antenna.  At the same time, I did enter Stew Perry with it and worked a LOT
of stations around the country, no problem with 100W.

My base loaded 60 footer is much better (~6dB more than the 40 footer by
field strength measurements on the day of the switch), but still not
necessarily " good," by some absolute definition.  Unless I have a
surprisingly low impedance ground system by accident, my 60 footer should
still be -6dBi or so.

But I work into Europe all the time, do great working domestically, and have
96 countries in the log with 100W.

I know that my antenna could be substantially better, but there are lots of
hams who would consider it an absolute smashing success.  The thing is,
whether the antenna is -6dBi or -12dBi, it's still better than nothing.
Even if it's -20dBi like a 43 footer with a balun and coax might be on 160m,
you could still do "surprising" and "wonderful" things with it.

One night, when LA7THA was booming in here on Topband, I turned my power
down to 5W and called.  I got a 339 report from Rune.  If you're new to
Topband and feeling good about your antenna, and you apply a full gallon
1500W to a -20dBi antenna, you still radiate 15W of it, and are a big 11dB
over my 1.25W radiated power for my LA7THA contact.    Heck, you're  within
a couple dB of what I estimate I'm radiating on 160m with 100W every night I
get on.  I've almost worked enough countries for 160m DXCC with what I
estimate is 25W EiRP.

Combine the fact that if you're on the East Coast, you can work 160m DXCC
with 25W EiRP, and the fact that people believe that it's gospel that to
work DX on 160m you need full legal limit, and you've got a recipe for
considering even an UNLOADED 43 foot vertical as a good 160m antenna.

I doubt too many hams care if their 160m DXCC certificate comes with an
Greenpeace seal of approval for "Green DXCC" for energy efficiency in ham
contacts ;-)


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