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

Jim Brown jim at audiosystemsgroup.com
Mon Oct 19 23:00:54 EDT 2015

On Mon,10/19/2015 7:00 PM, Rich Hallman - N7TR wrote:
> 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.

I have no experience, so will leave most of this to others. The 
fundamental cause though is less than ideal electrical contact in a 

> Thoughts about grounding the top section to the bottom when fully extended?

Definitely. Should be a short fat conductor from the bottom of the top 
section the top of the lower section that it mates with.

> Was thinking of grounding the coax at the top and bottom of the tower?

This is ALWAYS good practice, to prevent arc-overs between the tower and 
the coax, which will fry the coax at the point where the arc occurs.

73, Jim K9YC

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