[Elecraft] ?OT? Grounding/Protection question...

[k4wtf@enterzone.net]

On Fri, 23 May 2003, Stuart Rohre wrote:

> John, your set up for protection sounds pretty good, but 16 feet between
> ground rods is a half wave at 10m,  and  a quarter wave on 20m, so watch for
> any RF in the shack issues on those bands.  It may be just fine, as a half
> wave repeats whatever impedance it sees at the other end, but I try to stay

I hadn't considered that but, I don't think that it will be an
issue.  The ground system runs perpendicular to the antennas and beyond
that, it is earthed, as in 8-inches below ground, and hopefully, if all
works as designed, should be at ground potential.  I chose 16' between
ground based on the effective ground field achieved by a single rod.  The
"fields" of each rod don't overlap but are within about 8-inches of each
other.  I've been told that I could get away with not putting ground rods
on the path between the SPG box at the service entrance and the "dog
house" where the remote coax switch is located.  There are ground rods at
both ends of this ground bus but, I decided that it couldn't hurt to have
more copper driven into the ground.  It just gives more surface contact
for the ground bus to shed energy from a strike.


> away from lengths that fall into ham bands.  The band of most concern is
> where you have a quarter wave ground length, and that is 20m, but the
> effective length should be from rig to first ground rod.  Sometimes, you
> just cannot avoid some length getting ground outside the shack.

I haven't measured the length from the shack to the first ground
rod.  It's not terribly short but, not terribly long either.  It runs the
length of the house actually parallel to the dipoles but, in the basement
some 70ft vertical and 100+ft horizontal from them.  I don't anticipate it
being a problem though.

73, John - K4WTF