After 2nd cup of coffee I want to mention that a 2 element yagi or quad (
driven element and reflector will not only reject some of the signal from the
back side of the beam but also help push the signal to the front side of the
beam. The directing element or elements enhance that forward motion of the
signal.
Bill
----- Original Message -----
From: Bill Stone via BVARC
To: Willis Cooke ; BRAZOS VALLEY AMATEUR RADIO CLUB ; Gayle Dotts
Sent: Monday, July 28, 2014 10:46 AM
Subject: Re: [BVARC] F/B switch search
Hi Gayle,
Not sure what we are trying to switch... If I got where you are talking about
the F/B or front/back is a ratio of rejection the rear element (reflector) of a
yagi or quad supresses the rx/tx signal on the back side of the antenna. Thus
say a dipole (driven element) will give equal radiation pattern broad side
front and back. the reflector on a beam ( longer element) rejects signal to the
rear. A directing element ( director) shorter than the driven element in a 3
element yagi or quad enhances the forward direction of your signal. multi
element beams only add directors to the antenna each being abit shorter than
the directing element behind it. Say a 5 element beam is 1 driven element, 1
reflecting element and 3 directing elements. The more directors the further out
your signal is directed and the more rejection of signals that are not lined up
to the front of the beam . If I am on the same page with you there is no
switch, as to why we use an antenna rotor to pin point the DX wanted in the log.
Hope I read this right and after another cup of coffee I will review the post
again.
73 Bill WS5H
----- Original Message -----
From: Willis Cooke via BVARC
To: Gayle Dotts ; BRAZOS VALLEY AMATEUR RADIO CLUB
Sent: Monday, July 28, 2014 9:30 AM
Subject: Re: [BVARC] F/B switch search
It depends on what antenna you are talking about. There is no generic
front-back switch you can buy.
Sent from my iPhone
On Jul 28, 2014, at 8:57, Gayle Dotts via BVARC <[email protected]> wrote:
I don't see any front to back switches in an internet search. What do
you advise for one using a directional antenna that has front/back capabilities?
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