[Antennaware] New K9AY Observations

RFD fdavis at nfld.net
Tue Oct 14 07:08:27 EDT 2008

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 earth.

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

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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