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Re: [TowerTalk] 4 Square phase line length question

To: "Dan Levin" <>, <>
Subject: Re: [TowerTalk] 4 Square phase line length question
From: "Tom Rauch" <>
Reply-to: Tom Rauch <>
Date: Sat, 8 May 2004 19:31:00 -0400
List-post: <>
> Question: Do we need to take into account the length of
the wire in the coil
> (on CW) when we calculate the length of the RG-11 phasing
lines from the
> hybrid coupler to each element?  To put it differently,
are the coils part
> of the antenna, in which case we make the phasing lines
the right length and
> ignore the coils, or are the coils part of the feed line,
in which case they
> effect the length for phasing purposes?

Hi Dan,

Coils, unless they have low values of stray reactance to
"ground" compared to the termination impedance, behave
mostly like a pure reactance rather than a delay line. They
do not add significant phase delay like a delay line, they
just correct power factor. They really don't alter the
system at all, except for bringing voltage and current into
phase by canceling reactance.

Four squares already are very forgiving antennas anyway.
Phasing system designs from the very beginning were never
optimum from the very start of time with the four square
antenna. You can see a conventional 4-sq pattern (assuming
all currents are exactly equal and phases are PERFECT at 90
and 180 degrees) compared to the system I use with optimum
phasing at:

Hybrid couplers for example don't provide equal voltage to
each 1/4 wl feedline, which is required to force equal
current at each element. So they already don't do what you
need, yet the arrays are acceptable in performance despite
having current phase and ratio errors in the basic designs.

The antennas are obviously so forgiving, I wouldn't worry
about adding a tiny inductor. I'd  worry more about
installing a good radial system than the effects of a small

73 Tom


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