Topband: Quieting the transmit antenna duirng receive

[Thomas Kuehl]

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)