I currently use and have used for sometime a HyGain TH-11 at just over 70
feet. I also used LP's in the military..While I am working to improve my
"farm" I can hold my own working DX. As has been noted, the LP is designed
to work over a wide range of frequencies but do not produce an
overabundance of gain. Some are more particular as to routing of the
feedline along the boom. I have not found that to be the case with the TH-11
nor to have any issues with common mode. In general, the comments here about
75' height are probably about right although I know of one ham in SC who has
his TH-11 at about 150' which it would seem would leave a lot of holes.
Steve, WD8NPL
-----Original Message-----
From: Jim Thomson
Sent: Tuesday, February 14, 2017 12:15 PM
To: towertalk@contesting.com
Subject: [TowerTalk] LPDA optimal height
Date: Tue, 14 Feb 2017 07:23:58 -0500
From: "john@kk9a.com" <john@kk9a.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] LPDA optimal height
As you figured out, there is no perfect height. I would avoid going too
high where you create nulls at critical angles. My question is why do you
want to use a Log Periodic? I have never modeled one but they look to be
nothing more than multiple dipoles and they can have common mode current
if the coax is not properly routed around the hot boom. I used a small LP
once from the Caribbean and never felt loud.
John KK9A
## Optibeam has now re-written the book on LPs.
http://optibeam.net/index.php?article_id=131&clang=1
http://optibeam.net/index.php?article_id=135&clang=1
This lp has stupid amounts of FB on 5 bands.
For the OP, 75 ft would be a good compromise.
Jim VE7RF
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