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

[Jim Brown]

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 with crankups, so will leave most of this to 
others. The fundamental cause though is less than ideal electrical 
contact in a conductor.

> 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