RE: [TowerTalk] Grounding, Lightning & corona discharge

[Pete Smith <n4zr@contesting.com>]

At 03:57 PM 7/29/2004, Jim Brown wrote:
> When thinking about it, remember that the energy in lightning is NOT at
> dc, it is around 1 MHz. The impedance of that path is primarily
> INDUCTIVE REACTANCE, not resistance. Resistance (greatly
> increased by  skin effect)  will certainly produce the I2R losses, but XL
> will determine current!


I recall reading somewhere (I thought in Polyphaser material but can't find 
it there now, in a quick search) that there is meaningful energy in a 
typical lightning bolt that is effectively far higher frequency than that 
-- somewhere in the 100 MHz range -- because of the fast rise time of a 
typical strike.  This was in connection with advice that ground wiring 
follow VHF precepts in being as straight and wide as possible to absolutely 
minimize inductance.

Fact or fiction?  It would be a lot easier for me to improve my protective 
grounding if I could use copper strip but have a couple of right-angle 
bends in it.


73, Pete N4ZR
The World HF Contest Station Database
was updated on June 5, 2004
2728 contest stations at
www.pvrc.org/WCSD/WCSDsearch.htm  

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