On 2/14/17 9:15 AM, Jim Thomson wrote:
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.
I wonder about wire LPDAs (such as the one from TCI used in SW
broadcast).. they can be installed sloping, so that the elements for a
particular frequency range are at the same height (in wavelengths) above
the ground.
Of course, rotating such a LPDA requires towers on wheels or some such..
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