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[TowerTalk] Low TOA on 160 Verticals

To: "a Towertalk eList" <towertalk@contesting.com>
Subject: [TowerTalk] Low TOA on 160 Verticals
From: "Thomas Giella KN4LF" <kn4lf@earthlink.net>
Date: Tue, 3 Apr 2007 12:24:59 -0400
List-post: <mailto:towertalk@contesting.com>
Yuri K3BU Said:

If installed over salty marsh. Ever tried to model or compare any vertical 
over average and "perfect" sea ground and see the gain at LOW angles?

Thomas KN4LF Says:

Speaking of low angles, when it comes to 160 meter vertical antenna's you 
can get a bit of a lower take off angle (TOA) from a full 1/4 wave vertical 
or electrical 1/4 wave tee vertical of 10-20 degrees, versus ~30 deg. with 
the inverted L. However it's an exercise in futility as the nighttime E 
layer MUF blocks 160 meter low angle transmitted radio signals from ever 
reaching the F layer to be propagated. So unlike with HF propagation, MF 
propagation success does not require the lowest of take off angles to work 
DX.

Also higher take off angles of ~30 degrees via the inverted L are better 
able to take advantage of the low signal loss E valley-F layer propagation 
duct mechanism, a form of Chordal hop propagation.

- -... ...- -,
Thomas F. Giella, KN4LF
Lakeland, FL, USA
kn4lf@earthlink.net

KN4LF SWL & Amateur Radio Autobiography: http://www.kn4lf.com
New Scientific Evidence for the Existence of God: 
http://www.cosmicfingerprints.com/audio/newevidence.htm

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