Try this, remove the coax and open the feedpoint of the inverted transmit L.
This will make it invisible. The tower is another story, but try this
If the signals on 160 show directivity then you found the problem. A relay
will have to be installed at the base of the 160m antenna that opens when
you are in Receive.
[mailto:email@example.com] On Behalf Of RFD
Sent: Tuesday, October 14, 2008 6:08 AM
Subject: [Antennaware] New K9AY Observations
I have had a K9AY in operation now for a couple of weeks. Using the WX0B
control and relay boxes and the antenna is fed with RG6 with F connectors.
It is 40ft east of my 52ft tower and 160M coaxial Inv "L". I built the two
loops from scrap wire and fibreglass tent poles ..height 25ft. The NE loop
is made from insulated 14ga. house wire and the SE/NW loop from enamel
coated 14ga copper.
It may be my imagination but the enamel coated loop always sounds more
"alive " then the other one. In either case there is plenty of signal coming
to the FT1000MP so that I rarely use the on board control box preamp. Have
placed four 25ft radials on the grass under the loops and bonded same to a
4ft copper ground rod that was successfully pounded into our flint like
The NE loop is actually oriented a bit to the east of north so the panel
markings on the control box don't actually lineup with the orientation of
the two loops.
No other antennas closer to the loops.
I notice that directivity of the loops on the BC band from below 1600khz is
dramatic to say the least. Eu BC stations on SE loop for are practically
unreadable on the NW (west) loop. Likewise USA BC stations on SW loop (west)
and gone completely on the east loop.
The loops appear to work properly on BCB freqs which are far away from the
resonance freq of the 160M Inv L.
On 160M however directivity of the loops is not dramatic at all.
Many signals are the same strength on all loops. Some signals from Eu appear
to be stronger on the East loop but not all the time. USA stations appear to
be same on NE and NW loops. The switching of the termination resistors
appears to be working as I can notice changes ion F?B when I vary the
resistors while listening to BCB stations.
So I am concluding that the tower and the Inv L are screwing up the loops on
160M.? The loops are actually near ends of several radials for the "L". I
have tried decoupling the Inv L at the shack end of the Inv L coax by
alternatively opening it and also grounding it to the station ground....but
see no difference on loop rec'd signals.
Have not yet tried decoupling schemes right at the base of the "L".
Also I am not yet using a common mode choke on the RG6 feedline of the
loops. I do have a "choke" at the base of the "L"...consisting of 12 turns
of RG58 on a 2.5 inch toroid of unknown specs.
Anyone have any suggestions on the best (easiest) way to decouple the "L"?
73 Frank VO1HP
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