Height above ground
to be determined
By Andy Ikin, Wellbrook
K9AY web group, September 15, 2000
I think some experimentation is required determining the
distance above ground of the lower part of the K9AY loop.
My experience is that laying the loop on the ground will degrade
the front-to-back, F/B, ratio.
I suspect in my case that the E field response of the loop was
reduced, hence I couldn't balance the E and H field output with
the Vactrol to achieve a null.
I suspect that this feature is also related to the ground conditions.
By Patrick
Martin, USA
K9AY web group, September 15, 2000
The other day I dropped the horizontal leg on the antenna right
on the ground. It was up about a foot.
I found today, in checking the termination, that the nulls were
poorer. So I raised the antenna back up to the one foot level.
It worked better again.
I tried something different. On the east end of the antenna I
raised it about two feet, so the antenna slopes downward a bit.
The nulls improved on groundwave.
I tried raising the antenna on the east end even higher, to the
three foot level, but the nulls worsened again.
So now I'm stuck with the two feet on the east end and one foot
on the west end, and it's pretty good.
Another interesting thing about the antenna: any movement of the
wire affects the nulls. The antenna is very sensitive to any changes,
any. Is this normal?
If so, the antenna is going to be tough to use during the high
winds in the winter.
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