[TowerTalk] Ground Rods

Tom Rauch w8ji at contesting.com
Tue May 4 14:34:40 EDT 2004


> Just a guess here........Could it be that the low
resistance required is to
> allow the tower to bleed off the charge easily and thereby
reducing the chance
> of a direct hit?  Is there anybody out there who is more
of a tech than I am,
> who would know for sure?


Hi Bill,

A Physicist friend of mine suggested something similar and
that currents were very high from corona.

I put a 100A meter from my insulated 300ft tower to ground
and saw no deflection at all in nasty weather when the tower
had corona. A 1mA meter danced all over the place, sometimes
at full scale.

My conclusion is the ground current, short of a strike, is
certainly in the milliamp range in many cases. Even 1000
ohms would bleed everything off quite well.

The problem is always the hits, and I don't think anything
except lowering the antenna or making it "blunter" helps
that. The voltage is in the clouds, the earth is a huge
charge source or sink and unless you somehow discharge the
clouds the potential remains what it is. In other words the
tower or antenna isn't what is moving around in potential,
the clouds are.

73 Tom




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