Topband: Modeling Transmit Antenna Affect on Rx Antenna Performance?

Guy Olinger K2AV k2av.guy at
Fri Sep 30 15:31:57 EDT 2016

Hi Paul,

Modeling the effect of the feedline and the receiver terminating the
feedline is tricky. Some are able to short or open the TX feedline in the
shack due to a "favorable" length from the antenna to the shack. The brute
force method is to install a vacuum relay at the feedpoint which leaves the
feedpoint hanging on RX. That's tough for QSK, but can be done based on a
microHam or WinKey box, used as keyer both to paddle and contest software.

You also need to consult the mfr of the RX array which may have limits to
the amount of induced voltage to the Hi-Z. So until determined otherwise,
you have a TX bothering RX on TX issue in addition to a TX bothering RX on
RX issue.

73, Guy.

On Fri, Sep 30, 2016 at 3:20 PM, JC <n4is at> wrote:

> My TX antenna is 60ft from my vertical WF and my horizontal WF is at the
> top
> of my TX antenna.  I am using a Folded Unipole configuration, it is  a
> skirt
> with 3 wires forming a cage.  The skirt detune the tower during RX and help
> the TX with a huge broad band.
> In your case, just open the T disconnecting it from the coaxial cable using
> a fast vacuum relay. This will to the same as my UNIPOLE.  Just keep the T
> floating during RX.
> 73
> JC
> N4IS
> _________________
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