[TowerTalk] Tower grounds

Jim Lux jimlux at earthlink.net
Wed Jun 13 08:02:13 PDT 2012

On 6/13/12 7:46 AM, John Langdon wrote:
> I favor the strap over wire for lighting because of the larger surface area
> bang for the buck.

but surface area doesn't buy you anything for lightning or electrical 
safety grounds.  increasing surface area doesn't markedly reduce the 
inductance.  All it does is decrease the AC resistance (skin effect and 
all that).  And if you're in a corrosion prone environment, more surface 
area is worse.

For transient protection, it's inductance that's important, not resistance.

For vertical antenna ground fields, AC resistance is important.

If you're building a AM (or topband) vertical antenna, then using strap 
makes sense: kill two birds with one stone..

Or, if strap is mechanically more convenient.  I'd rather drill holes 
and bolt 1/16"x1" copper bar than the same cross section round wire.

> Also, there are really three grounds to consider: lightning, radio, and
> legal/building code ground.
> 73 John N5CQ


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