Definitely agree with George, W5YR, that you should forgo the outside ground
rod connection, if the distance to it is any length of 8 foot or more.
Other clues to the proximity feedback from beam to shack, are do you have
more of a problem on some bands than others?
The tower is pretty close to a quarter wave on 40m, thus it might be an
issue, since it is also a good radiator at 15m harmonic of 40.
Make sure your boom is bonded AROUND the rotator with a flexible lead to the
tower top. Use your ground rods at each tower leg or use crowfoot grounds
at the tower legs to provide static and lightning discharge. Remember to
disconnect the rigs and accessories from all antennas when any storms are
near, or coming, since you are going to use the star common bus of the
equipment, and not rely on distant ground rods.
A simple Ge diode detector across a 100 micro amp meter may allow you to
"sniff" for strong RF fields in the shack. Use a stiff short wire for a
whip sense probe antenna. Is RFI more when the beam is pointed a certain
direction? Sometimes decoupling the rotor cable with ferrite chokes and
cable choking may block any RF feedback over that path.
73, and GL, let us know what you find.
Stuart K5KVH
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