[TowerTalk] TS-940 Overload?

[Jim]

I noticed wen I lived near several broadcast stations that if I did not have
a low impedance (at broadcast freqs) balun at the feed point, I got
broadcast interference. If I put a balun in, the problem disappeared.
I used a tri-filier wound unit. When using my th6dxx, there was no problem
at all. The th6 has a "shorted" feed point (at broadcast freqs) by the
hairpin match.

73 and good luck...

Jim W7RY

-----Original Message-----
From: K7NT@aol.com <K7NT@aol.com>
To: towertalk@contesting.com <towertalk@contesting.com>
Date: Tuesday, March 02, 1999 11:42 PM
Subject: [TowerTalk] TS-940 Overload?


>
>I recently put up an inverted vee for 80 and 40, hung off the top of my
>LM-470E 70' crank-up tower. I noticed that when I went to listen on it, I
had
>a horrendous 20 dB over 9 noise level that was not there on my other, lower
>40m antenna.
>
>I tried putting in 10 dB attenuation on the TS940 and the problem went
away!
>This antenna has proven to be a good performer, as long as I put in 10 dB
>attenuation on the 940. This holds true for 80m as well as listening on 20
and
>15.
>
>The other antenna, which does not exhibit these problems, is a Hygain
Explorer
>14 with a 40m kit mounted on a tripod on the roof at about 25 feet. (BTW,
the
>inverted vee whips the shortened 40m rotatable dipole by as much as 2
S-units,
>as expected).
>
>I know that there is a strong AM broadcast station about 2-3 miles from me,
>which has interfered with the telephones, but I haven't had any trouble
from
>it in a couple years.
>
>I am assuming that I am experiencing an overload situation, which must be
>pretty severe, since when I add the attenuation, the S-meter falls from 20
dB
>over 9 to a more normal noise level of S-2 or 3. The overloading signal
must
>be really driving some receiver circuit "crazy" to generate that much
>noise/distortion.
>
>I am interested in any opinions on what is going on here. Is my 940 broken
>(bandpass filters not working, other circuit problems)? I am considering
>adding a high-pass BCI filter to see if that helps. Any recommendations on
>filters?
>
>If this is not the right place to discuss this, sorry. Thanks for any
ideas.
>73,
>Mike  K7NT
>K7NT@aol.com or MConatore@yahoo.com
>
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