[TowerTalk] LPDA optimal height

[Steve Baughn]

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 at contesting.com
Subject: [TowerTalk] LPDA optimal height

Date: Tue, 14 Feb 2017 07:23:58 -0500
From: "john at kk9a.com" <john at kk9a.com>
To: towertalk at 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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