Topband: Quieting the transmit antenna duirng receive

[Guy Olinger, K2AV]

If you use an MP, you can use the menu to set a running fixed delay 
between key down and power out on CW. This causes the entire cw 
waveform to be continuously delayed by up to 30 ms. This is like a 
very short "tape delay". This is not to be confused with the "vox 
hang" type delay that can also be set from the menu for CW.

Use dit or dah closure from the keyer to run the switching of amps and 
antennas, and set the MP's running delay to not transmit until enough 
time has passed for all the relay state changes to complete.

This kind of delay setting may exist on other rigs but I can't vouch 
for them.

73, Guy.

----- Original Message ----- 
From: "Thomas Kuehl" <ac7a at earthlink.net>
To: <topband at contesting.com>
Sent: Friday, October 01, 2004 10:07 PM
Subject: Topband: Quieting the transmit antenna duirng receive


> Hi,
>
> I am getting serious about installing a K9AY receiving loop. I've 
> been told
> that one should "quiet" the vertical transmit antenna when using the 
> receive
> antenna. Otherwise, it will reradiate the local noise and compromise 
> the
> receive antenna's performance. When taking the proper factors into 
> account
> this can be accomplished by shorting out, or opening the vertical's
> feedpoint. My plan is to use a fast vacuum relay for the switching 
> function,
> but as we know it is best not to hot switch the relay. Therefore, I 
> need to
> provide a delay before the transmit RF is applied. One that won't 
> result in
> the CW characters to be shortened.
>
> Can someone direct me to, or provide some information on how to best 
> provide
> the delay?  I've been toying with some ideas, but I may be 
> reinventing the
> wheel and probably won't come up with the best solution.
>
> Thanks in advance, Thomas - AC7A (Tucson)
>
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