[Heathkit] Differntial earth

[KB9GKC at aol.com]

In a message dated 2/4/2006 5:44:57 P.M. Central Standard Time,  
RMcGraw at Blomand.Net writes:

Station  ground must be bonded 
to the AC mains ground.  Failure to do this  will place the radio equipment 
between grounds of two different potentials  during a nearby lightning 
strike.  Most think that ground is  ground.  


Excellent post Bob,
 
I would also like to add the following:
 
I will call the spot that lightening strikes as Ground Zero.  For  example if 
a lightening strike hits ground zero and has 100,000  volts.  As we get 
further from Ground Zero the voltage drops.  So  hypothetically we have 90,000 
volts 10 feet from Ground Zero and 70,000 volts 20  feet away.   Say we could take 
a volt meter and measure the voltage  between Ground Zero and 10 feet away, 
we would read a 10,000 volt differential,  it is this differential that we need 
to avoid and thus we tie (bond) all the  grounds together, RF ground, AC 
ground at the electrical  panel, tower  ground.  This way the ground potential 
between all our grounds ride up and  down together rather then having a voltage 
differential that destroys our  equipment.
 
Hope some find this info useful,
73
Douglas