Rob,
Kevin Kidd of AM Ground Systems could learn from us mere amateurs.
You don't necessarily need to "spend the money" and use copper mesh.
Jim mentioned Rob Sherwood's contribution of using galvanized ground
screen. I used his
ground screen system he presented and had great results. Still intact
when I took it up.
I had the four sections of galvanized mesh extending out in four
directions and used it for years until recently when I went to elevated
radials about 12 feet above the ground. As Jim stated with the chemical
makeup of our soil at any given QTH it may work in one location and not
another. Its not very expensive and worth trying. In my case it worked
well. Your premise that we should not use the galvanized mesh cannot be
regarded as universally valid. It is a good option to "try" at our
individual stations. Certainly more cost effective than copper
mesh.............
Bob
K6UJ
On 10/28/16 3:42 AM, Rob Atkinson wrote:
Some pretty sharp engineers disagree with this advice. Rob Sherwood, NC0B, first
published on the usefulness of galvanized ground screen in 1977, and talked about it
in >presentations in the Dayton Antenna Forum in 2008 and 2009. Rob is best known
for his work on quantifying the receive performance of modern HF rigs. Like anything
making >contact with the chemical makeup of soil and local moisture at any given
QTH, materials that work in one location may not work in another.
You can go to all the trouble of putting down "mesh" and risk having
to do it all over again since that is a material and product not
intended to be in contact with the ground.
Or you can spend the money and do it right from the get-go, except
that in professional installations, copper mesh or screen, is only
used with voltage fed towers. For most ham situations the tower base
is a current maximum, i.e. a 90 degree radiator base fed, and for that
a radial ring and ground system made up of radiators is fine.
Who are all these "sharp engineers?" Kevin Kidd of AM Ground Systems
Inc. has probably done more professional AM tower ground system
installations and re-builds across the U.S. then all of your "sharp
engineers" combined.
There's nothing wrong with being a cheap ham at the hamfest, but the
ground system is one area where cheap just buys trouble within a year
or even a few months.
73
Rob
K5UJ
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|