Topband: Receive Antenna interaction with Transmit Antenna

[Guy Olinger K2AV]

The short answer is you have two choices.  De-resonate the TX antenna
during RX or get at some distance from the TX antennas.  Your modeling is
telling you what the interactions are, and therefore telling when you have
succeeded and when not.  Coming up with the solution on a given piece of
land with what you already have can be a really nasty chess game.  You may
need to change your ideas for TX and RX antenna(s) to make it work at your
place.  There are no easy answers.

Yes, the interactions are pretty bad indeed.  Quite a bit more, I would
guess, than you had imagined.  Making and maintaining an "entire property"
model (EPM) of all the conductors at Chez Glenn is a really good idea.
 Then, don't bother to buy wire or cut anything until it works in the
model.  Be sure that you have buried conductors, towers, roof gutters and
everything else in your EPM.  Keep it up to date.

73 & HNY,   Guy.

On Tue, Dec 27, 2011 at 11:17 AM, Glenn Biggerstaff <ww4b at ww4b.net> wrote:

> Hi everyone. I am in the process of building some new receive antennas
> and have been modeling a number of choices .My Transmit antenna is a
> full wave vertical loop 70 foot high and about 210 feet long .Currently
> I have a pair of short (28 ' ) base loaded verticals toward EU phased
> with a DX Engineering NCC-1 and one 550 foot beverage toward EU .They
> both work fairly well toward EU ,I would rate them about the same . I
> have been considering some type of circle array but it would be fairly
> close to the loop ~ 175 ft. When I start modeling vertical receive
> arrays the interaction is quite bad .I have been unable to come up with
> a scheme to detune the loop from the shack ,the only way I have come up
> with so far requires a relay at 2 points on the loop. Beverages in the
> same area don't seem to be affected very much . I understand about the
> need to limit the rf the receiver sees, I am just concerned about how to
> limit the degradation of the receive array .
>  Question 1 Are receive arrays with active antennas less affected than
> arrays with passive elements . I don't know how to model the active
> antennas . Do you just put a high resistance load at the bottom of the
> vertical to simulate the amplifier ?
>  Question 2  Is there a better way to detune the loop ?
>     Lastly  am I too concerned about the interaction on receive antenna
> performance ?
> Thanks for you time .
>
> Glenn WW4B
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