Topband: Vertical antennas aren't always best for DX
john.kaufmann at verizon.net
Mon Nov 26 20:53:27 EST 2018
The statement that the half of a horizontal dipole's radiation is vertically
polarized is misleading and needs qualification. There is a vertically
polarized component off the ends of the dipole but it is only of consequence
at takeoff angles approaching 90 degrees, in other words straight overhead.
I would argue that these takeoff angles are of little interest for long
At takeoff angles lower than 60 degrees or so, the total radiation pattern
of a dipole at any reasonable height becomes dominated by the horizontally
polarized component that is broadside to the dipole. The lower the angle
or the higher the dipole, the more insignificant the vertical component
becomes. This is all verifiable in EZNEC. If this were not true, you would
not see the well-defined radiation patterns that are produced by HF Yagi's
at higher frequencies were the radiation is horizontally polarized for
virtually all signals of interest.
73, John W1FV
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of
n4is at n4is.com
Sent: Monday, November 26, 2018 11:06 AM
To: 'Roger Kennedy'; topband at contesting.com
Subject: Re: Topband: Vertical antennas aren't always best for DX
Every dipole or inverted V irradiate 50% of the power horizontal polarized
broadside with the wire and 50% of the power vertical polarized along the
wire. After the first refraction it does not matter.
This is an electro-magnetic wave law. You can check that on EZENEC, it is
not a anecdote.
The advantage over vertical 1/4 wave antenna is efficiency. The vertical
efficiency depends on the ground plane resistance, it is common to see
invert L with only 50 % irradiated power, the other 50% is dissipated on the
"In Theory, we know everything, but nothing works"
"In Practice, everything works, but we don't know why"
We never will fully understand the 160m band.
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