[Towertalk] Grounding mast to tower

[n4kg@juno.com]

The HAM series rotors have ~48 bearings in the races.
With the weight of the mast and beam sitting on the rotor,
I expect it makes pretty good contact.  I measured a
very low resistance across a spare rotor with no external
load on it.  

To the best of my knowledge, I've had ZERO 
direct hits on any of my 7 towers which range from 
40 ft to 130 ft. in the 23 years I've been at this location.

All towers are 'in the ground' and all feedlines go down
to the ground where they are placed in shallow open
trenches to the house.  NO Polyphaser stuff anywhere.

I have seen lightning strike in a field 500 ft North of me, 
hit the power transformer next door, and split a tree 
across from next door.  The only lightning damage I
have experienced came in on my power lines.

FWIW, I've NEVER read a TowerTalk post declaring 
"my bearings welded over following a lightning strike".
( Is you background in physics? )

Tom  N4KG

On Tue, 2 Apr 2002 21:03:34 -0600 Pete Goudreau <goudpj@mac.com> writes:
> n4kg@juno.com wrote:
> 
> > Assuming you also have a rotor,
> > the mast will be grounded to the tower
> > through the rotor.
> 
> Yeah, that's true but that's through the rotor's bearing as well.  
> I'd bet that most rotors use bushings and that would be a lot better 
> 
> than a ball bearing.  I have no real idea though.
> 
> Thanks very much,
> Pete, AD5HD


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