[TowerTalk] RFI Broadcast Station Mixing in Crank-Up tower?

[David Robbins]

I have had to add bypass caps on some rotors also.  many dc controlled rotors like the yaesu g series use diodes in the rotor across the stops microswitches to only allow rotation in the other direction when you are against a stop, those 'should' be shorted unless you are in a stop.... however, the g2700 and g2800 also have a 'near the stops' slowdown feature that has 2 diodes that aren't shorted normally and could cause problems.


Oct 20, 2015 12:21:53 PM, aa4nu at comcast.net wrote:

Interesting challenge ... in both situations, have you tried to disconnect
and ground the rotor control lines and/or any remote switch lines, just to
see if that makes any difference. 

I seem to recall Ward, N0AX mentioning how he had to put bypass caps on his
rotor lines at one time to resolve a noise issue in an older NCJ article?

"Eliminate Noise Generated by Rotator-Control Boxes N0AX 95 Sep/Oct 35"

Perhaps a review of that text might help with both situations that could 
move you toward practical solutions?

73 de Billy, AA4NU

----- Original Message -----
From: Bill Parry

I have the mixing problem and my tower is not a crank up. It is 120 feet of
Rohn 25 with insulated guy wires. I notice it on 160, 80, and 40. I have no
idea what is causing it.

Bill W5VX

-----Original Message-----
From: Rich Hallman - N7TR

Has anyone had any problems with intermittent mixing from a close broadcast
station with a Crank-Up tower? I think I may have an issue with one of my
towers. Cranked up I hear mixing all over 80 meters (Every 10
KC).....Cranked down its gone. I already eliminated the antennas. Mixing
gets very intermittent in wind as the tower moves around.

Thoughts about grounding the top section to the bottom when fully extended?
Was thinking of grounding the coax at the top and bottom of the tower?

Thanks....


Rich N7TR
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