I need some help on a problem that has developed on my 160 meter full
wave quad loop. I have had the antenna up for about three years, and it
has preformed wonderfully. It is what I use for local work on 160, 75,
and 40 meters. It is fed with 450 ohm ladder line, and I run a home
brewed balanced balanced (two roller inductors and a var. cap.) tuner. I
have a kenwood 850 rig. The receive on the rig has been great until
recently. I have started picking up all sorts of out of band
transmissions. I hear AM radio stations all over the place. Airport
beacons, cw signals are every where, and in general I am just hearing a
lot of things I shouldnt be hearing. It got so bad I sent my rig off to
have it repaired. Guess what, there wasnt anything wrong with the rig.
As a matter of fact when I got it back it was the same as it was when it
left, so I sent it to a different repair facility, and they told me the
same thing, they could not find a thing wrong with the rig. I then
hooked up a friends short wave receiver to the antenna, and it had the
same problem with my antenna as my 850 had. This is really driving me
nuts. The antenna loads and works as well as ever as far as swr and the
receive is as strong as ever on the stations I want to hear, but it is
also too strong on the ones I dont want to hear. I have an AM 1000 watt
station about a mile from me, and I hear that sucker real well all over
the place. Before this problem started I never heard it at all, not even
on its harmonic frequencies. This problem did not start all at once, but
built up over about a 4 month period. Before it started I never heard
any of this mess at all, not a peep. I have one splice in the antenna,
but I have redone the splice, and resoldered it also. The total lenght
of the antenna is around 530ft as best as I can remember. I have not
redone the feedpoint yet, I guess that will be my next move, but I sure
would be thankful for any input anyone may have on my problem. How do I
get rid of this out of band harmonic junk?....Thanks for taking time to
read this long mess...73...
Tom Hix
W4th
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