Yup. You have a poor connection between your station ground and tower
ground. The T2X rotator uses a 3 conductor cable to provide a.c. power to
the controller, the green wire is at a.c. ground and the direction indicator
wiper in the rotator is also at ground potential. With a poor bond between
the tower and station ground the potential at the wiper will have a voltage
on it (depending on the direction of the antenna) and that voltage will
appear on your coax line and generate the hum you are experiencing.
The quick fix is to lift the ground (green) wire in the control box but the
correct fix is to bond your station ground to your tower ground.
I had the same problem and it about drove me crazy. Blew components in the
front end of my IC-765 several times before I finally determined what was
causing the failures.
de Paul, W8AEF
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ZF2TA FO8DX FO0PLA 8Q7AA XZ0A
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----- Original Message -----
From: "Dan Levin" <djl@andlev.com>
To: <towertalk@contesting.com>
Sent: Thursday, September 18, 2003 6:30 PM
Subject: [TowerTalk] T2X Control Box Creating RFI
> I vaguely recall a thread on this in the past, so
> my apologies if this is a repeat. I can't find
> the old thread in the archives...
>
> I have recently isolated my rotor controller box
> as the source of a long standing "feedback" problem
> in my shack. When the rotor controller is connected
> to the rotor, and the antennas are pointed in certain
> directions, I get a "roar" on my transmitted audio
> if I transmit with more than a certain amount of
> power.
>
> The amount of power depends on the directions that the
> antennas are pointed in (big surprise). If the rotor
> controller is not connected to the rotor, the noise
> goes away. The controller is a standard Hy-Gain
> Tailtwister controller.
>
> Does anyone have experience with such a problem,
> and hopefully a recommended solution. Please be
> specific, my technical expertise in this area is
> less than might be desired :-)
>
> Thanks much!
>
> ***dan, K6IF
>
> See you all in the California QSO Party,
> October 4-5!
>
>
> ***dan
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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