While not strickly antennas, this is a rotator problem.

I have a Ham IV that when I turn on the brake the receive signal takes on a
60 or 120 hz hum . I though it might be the control box too close to my
Icom 746 PRO. I have a switch box connecting two lowband wire antennas and
a triband beam to the Icom. If I listen to a signal on the wire antennas I
do not get the hum modulation on the incomming signal when I rotate the
beam. Those coax wires are not near the rotator wires. This tends to
eliminate the transfromer of the rotator box from getting into the Icom by
magnetic coupling. If I switch to the beam , then turn the brake on the
rotator box I will get hum modulation. The triband is fed with some Davis
Bury flex (foil and braid shield coax) and the rotator wires are taped to
the coax for a distnce of about 100 feet.

The antenna does not have to ratate, just mashing the brake release button
will make the signal hum modulate on receive.

The Icom is being powered by an Astrom 50 amp supply and the rotator plugs
into the 120 vac outlet.

Has anyone else ran across this problem ?

Yes, many years ago. I think your rotor control box has a 3 wire plug. Use a
3 wire to 2 wire adapter for the plug and the problem will go away.

There may be a more "high tech" solution, but this one is quick, if dirty.


"Ralph Mowery" wrote in message
k.net...
While not strickly antennas, this is a rotator problem.

I have a Ham IV that when I turn on the brake the receive signal takes on
a 60 or 120 hz hum . I though it might be the control box too close to my
Icom 746 PRO. I have a switch box connecting two lowband wire antennas
and a triband beam to the Icom. If I listen to a signal on the wire
antennas I do not get the hum modulation on the incomming signal when I
rotate the beam. Those coax wires are not near the rotator wires. This
tends to eliminate the transfromer of the rotator box from getting into
the Icom by magnetic coupling. If I switch to the beam , then turn the
brake on the rotator box I will get hum modulation. The triband is fed
with some Davis Bury flex (foil and braid shield coax) and the rotator
wires are taped to the coax for a distnce of about 100 feet.

The antenna does not have to ratate, just mashing the brake release button
will make the signal hum modulate on receive.

The Icom is being powered by an Astrom 50 amp supply and the rotator plugs
into the 120 vac outlet.

Has anyone else ran across this problem ?