There is no single solution for detuning an antenna it depends on
electrical length. For verticals a quarter wavelength or less it is
common to have a contactor between the network and the radiating element
and open the connection to float that element. This is the practice in
commercial
.
Carl
KM1H
- Original Message -
From: W2XJ w...@nyc.rr.com
To: topband@contesting.com
Sent: Sunday, June 17, 2012 11:03 AM
Subject: Re: Topband: Detuning transmit antenna in receive
There is no single solution for detuning an antenna it depends on
electrical length. For verticals
I am very interested in this subject, I am trying to figure out how to detune
my 160 inverted L.I am using a flag antenna for receive and unfortunately
it is only about 50 feet from the base of the L.By itself the flag works
very well at reducing the local electrical noise, (which
My tower shunt feed for 160 and 80 is latching relay remote controlled. On 160,
certain orientations of my very close RX flag result in reduced signal due to
the influence of the tuned vertical. In those instances, I detune the shunt
by selecting 80m. My amp has a rather dramatic way of
The easy way to do that is with a relay between the coax center conductor
and the L wire at the feedpoint. When the relay is open, that makes the L a
1/4 wave on 160 which is not self-resonant. The quarter wave is only
resonant in conjunction with whatever counterpoise you are using for the L.
A previous edition (and maybe the current one) of
the Low Band DXing book has several methods of
detuning TX antennas...might be worth a look. Some
can be done right in the shack.
73
Charlie, N0TT
On Sun, 17 Jun 2012 13:37:55 -0700 Bob K6UJ k...@pacbell.net writes:
I am very interested in
OK, several folks came back and recommended detuning my transmit antenna in
receive.
Certainly any receive antenna I have is going to be in the shadow of my
transmit antenna, a 130-foot flat-top about 85 feet up, fed against ground.
(Really it's an 80 meter doublet fed with ladder line. I tie
Tim
Trying to figure out what detune is
Excellent question. The ground is the most important part of the T antenna,
without the ground the antenna became a 1/4 element isolated from ground
and wont irradiate. In order to accomplish that you need two fast vacuum
relay to open the ladder line.
