[TowerTalk] Tower grounds

Gary Schafer garyschafer at comcast.net
Thu Jun 14 16:05:07 PDT 2012

It has often been said, by Polyphaser, that "a good lightning ground also
makes a good broadcast band antenna ground".

This implies that all of the things that make a good antenna ground are also
necessary for a good lightning ground including radials, low AC resistance
and low inductance leads.

Gary  K4FMX

> -----Original Message-----
> From: towertalk-bounces at contesting.com [mailto:towertalk-
> bounces at contesting.com] On Behalf Of Jim Lux
> Sent: Wednesday, June 13, 2012 11:02 AM
> To: John Langdon
> Cc: towertalk at contesting.com
> Subject: Re: [TowerTalk] Tower grounds
> 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.

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