[Antennas] Radial Wires VS a wire or screen mesh

[Kevin C. Kidd CSRE/AMD]

Gentlemen,

I am a broadcast engineer of 26 years and specialize in broadcast AM and
AM grounding.

Steel anything in or on the ground is a bad idea long term due to
corrosion.  Steel also has a substantially higher resistance than copper
and hence is not as efficient.

I have never witnessed a location or soil type where steel or galvanized
steel would last longer than copper.  Not even close.  I rebuilt a site
in Cincinnati 2 years ago where galvanized steel horse fence wire was
laid upon the ground for the ground system.  It failed after about 5
years.  It never worked correctly even when new.  Copper wire can be
expected to last 30 years in most soils and FOREVER in a some.

I have heard many rumors thru the broadcast industry about ground
systems being built with alternative materials.  IE, Steel or aluminum
wire.  A few have certainly been attempted.  No long term successes have
ever been reported.

I have heard tales of a station up in the NE (NJ, NY?) supposedly
building a GS out of barbed wire but soon had to replace it with copper
due to failed radials.

In AM broadcast, copper is the standard and only viable alternative.
There is a new soft drawn copperweld wire that is being used some but it
has potential longevity issues as well.  I have used some of it on a
project where some of the radials were unprotected in a theft prone
area.  Scrap value for it is near $0 but electrically it functions
exactly like solid copper wire.

We also occasionally use an expanded copper mesh for near tower ground
concentration.  It is made from an 3x8ft sheet of .020in thick copper
and after slitting and expansion, ends up being 8x24ft.   It resembles
the expanded steel mesh used in catwalk gratings.  We don't use much of
it these days due to varying order lead times and cost.  End user price
is now over $500/roll (8x24ft).

Good luck,



AI4WM wrote:
> No reason why 4 X 4 or any other hardware wire, mesh or fencing would
> not work.  The idea is to make the near field ground as conductive as
> possible.  I have used all kinds of tricks including running the
> sprinklers to keep the ground wet to increase field strength.
> 
> Barbed wire has been used in commercial radio laid on the ground and
> some times just below the surface in high crime areas where the copper
> radials get stolen.  I worked with a consultant who did exactly that a
> few weeks after we spoke about it at a station he was assisting.  They
> were worried their license would need modifications since laying the
> barbed wire on the top of the ground did actually increase their 1V/M
> contour.
> 
> As a private citizen I do not think I would use barbed wire due to the
> liablity and in many towns and cities it would be flat out illegal.
> 
> 
> 
> On Thu, Nov 12, 2009 at 11:44 AM, Ron Youvan <ka4inm at tampabay.rr.com> wrote:
>>>  Does anyone know if a functional radial system can be made using fencing wire mesh, say 4
>> x 4?  If un-welded mesh were used and laid down the length of either 1/8 wave or 1/4 wave,
>> shouldn't it work as well as radial wires?  Or is it the radial symmetry around the driven
>> pole the key?
>>
>>   A great deal of it is the length.  American broadcast counterpoise systems are required
>> to be 120 wires evenly spaced, but there are concentric rings of wire that tie the radials
>> together creating a "mat" of wire, but the rings are soldered or welded to the radial
>> wires at every intersection.  In many locations (soil types) galvanized wire can outlast
>> copper, but making an efficient reflector for the 1/4 wl vertical antenna is the goal.
>> Un-welded, bad idea, solder or brazing the joints will work if the other criteria is met.
>> I would buy 133' rolls over panels of any kind.  (like "red top")  It won't be cheep, I
>> think buying solenoid windings wound with copper wire and such at HAM-fests and rolling it
>> out is the cheapest plan I have heard about.
>> --
>>    Ron  KA4INM - I'm proud to be Chuck's pop!
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> 
> 
> 
-- 
Kevin C. Kidd, CSRE/AMD
WD4RAT
mailto:kkidd at kkbc.com

KK BROADCAST ENGINEERING
http://www.kkbc.com

AM GROUND SYSTEMS CO.
http://www.amgroundsystems.com

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Lawrenceburg, TN 38464
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