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Wire separation
of the loops
Is
it important that the top of the loops have a certain separation?
There are no minimum separation requirements between loops.
I have two sets of two K9AYs and for both the two loops are separated
by about 1 inch - 25 mm. I use a piece of pvc pipe with two holes
drilled at right angles to hold the loops with each wire looped
one time back through the hole in the pipe to lock it in place.
If using insulated wire it probably wouldn't hurt performance even
if they touched at some point but I personally would always make
sure they were not touching - just to be on the safe side. If one
loop is slightly higher or lower than the other it will not hurt
antenna performance. (Al Merriman, k9ay list, July 31, 2000)
At a recent K9AY installation on the Coast, my K9AY was put
up with the crossed insulated wires touching at the top (an accident
not noted when it was put up! Ooops!).
There was no noticeable effect on the antenna.
Not sure I'd always want to repeat this, but the wires are insulated.
The crossing of the pair of wires ( or 4 wires) on a central mast
is just for convenience -- the use of a single portable mast in
my case.
Some (Guy Atkins comes to mind) have built the loops separated along
fence rows with the electronics at the corner.
Other reports have indicated the loops are entirely separate, and
fed from the bottom of the loop with 450 ohm ladder line connecting
the loops to the electronics. (Don ?, Oregon, USA, k9ay list,
July 30, 2000)
My own observations are that this is not important.
In fact the two loops can be shorted together at the apex with no
measurable affect.
I even connected a Capacity Hat to the top of the loops in a vain
attempt to improve performance, but I noticed no difference.
At the Head Unit in my installation the loop wires are wound around
the Earth the rod ( two turns and knotted ) to provide "strain relief"
before connection to the Head terminals. I am not sure that is an
important installation feature, however one could speculated that
the loop isolation at the Head is improved due the individual loop
capacitance to the Earth stake.
Other comments concerning the loop shape; delta or oblong depend
on whether the optimum null is for sky-wave ore ground-wave. Therefore
the loop shape should be determined by experimentation.
Personally, I find that the original Delta shape meets my requirements
for trans-European LW and MW listening. One word of word of warning,
if the any part of the lower loop wire gets too close or touches
the ground then this can destroy the F/B. (Andy Ikin, Wellbrook,
k9ay list, August 3, 2000)
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antennX 
Basics
Performance