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Re: Topband: Detuning transmit antenna in receive

To: "'Shoppa, Tim'" <tshoppa@wmata.com>, <topband@contesting.com>
Subject: Re: Topband: Detuning transmit antenna in receive
From: "N4IS" <n4is@comcast.net>
Date: Sat, 16 Jun 2012 15:46:35 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
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. 

The relay needs to be fast , 5 millisecond, slow relays will see RF and hot
switch. It can damage your amp.

The impedance on the feed line does not detune the antenna, short circuit
the feed line does not insulate the T from the ground.

You can see in my site www.n4is.com  how deteriorate a RX antenna can be
without detuning the TX antenna. My BigWF works very well 70 FT far from my
TX antenna when detuned, the BWF is useless without detuning my TX antenna.

Regards
Jose Carlos 

N4IS


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