Re: Topband: Radial Wire System Comparison - (was adding a parasitic reflect

[MICHAEL ST ANGELO]

Paul,

I got a good deal on stranded teflon wire. It cost me $0. I lay it on the 
ground. The only issue I have with it is that the wire is stranded and it wicks 
in moisture. Teflon is easily nicked and the moisture finds it's way in.

You mentioned your wire is solid so you should not have that problem. 

In any case I'd be hesitant in removing the insulation and soldering. The 
exposed joints may corrode.

I got my wire 25 years ago. At that time teflon was cheap because scrap dealers 
didn't like it. The overseas recyclers they shipped wire to burned off the 
insulation to get to the copper; That is not possible with teflon.

Mike N2MS


> On February 1, 2018 at 9:39 AM Paul Christensen  wrote:
> 
> 
> >"The reason is that the standard DA ground system as far as I know, has
> always involved strapping radials to a copper strap running along the line
> of radial intersection, clipping off the radial wire that runs past the
> strap."
> 
> Unless there's modeled or measured data, that's the "conventional wisdom,"
> -- and it makes sense in those commercial installations where it's
> impractical to use insulated wire that can withstand long-term soil
> conditions.  Or, is there really that much cross coupling that results in
> radial current cancellation when the wire is insulated?  
> 
> The wire is buried just below the ground surface and only the wire
> insulation would come in contact between radial wires.  However, the
> conductor-to-conductor distance at the overlap points would be very small.
> For the answer, I'll likely need to run a NEC 4.2 model, and assign Z axis
> distances of the radials that can be easily adjusted in NEC that results in
> anything from a wired cross connection point to any spacing distance in
> between radials.
> 
> >Why the teflon insulation?
> 
> Already acquired from a surplus supplier...a lot of it.  In addition to the
> Teflon insulation, it's solid, silver-tinned copper, 18 AWG.  
> 
> Paul, W9AC
> 
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Re: Topband: Radial Wire System Comparison - (was adding a parasitic reflect

[Paul Christensen]

>"The reason is that the standard DA ground system as far as I know, has
always involved strapping radials to a copper strap running along the line
of radial intersection, clipping off the radial wire that runs past the
strap."

Unless there's modeled or measured data, that's the "conventional wisdom,"
-- and it makes sense in those commercial installations where it's
impractical to use insulated wire that can withstand long-term soil
conditions.  Or, is there really that much cross coupling that results in
radial current cancellation when the wire is insulated?  

The wire is buried just below the ground surface and only the wire
insulation would come in contact between radial wires.  However, the
conductor-to-conductor distance at the overlap points would be very small.
For the answer, I'll likely need to run a NEC 4.2 model, and assign Z axis
distances of the radials that can be easily adjusted in NEC that results in
anything from a wired cross connection point to any spacing distance in
between radials.

>Why the teflon insulation?

Already acquired from a surplus supplier...a lot of it.  In addition to the
Teflon insulation, it's solid, silver-tinned copper, 18 AWG.  

Paul, W9AC

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Topband: Radial Wire System Comparison - (was adding a parasitic reflect

[Rob Atkinson]

 >> I have researched Laport's material, and find nothing that compares
multi-tower array performance when using insulated radial wire versus
uninsulated wire when using a bus wire at the radial overlap points.  Since
his worked in the 1950s mostly focused on directional broadcast tower arrays
-- and the use of heavy-gauge wire, possibly insulated radial wire wasn't
considered because of long-term insulation decomposition that one day
>> results in electrical contact between overlapping radials.

I doubt if you'll find anything in the broadcast literature.  The
reason is that the standard DA ground system as far as I know, has
always involved strapping radials to a copper strap running along the
line of radial intersection, clipping off the radial wire that runs
past the strap.  And the standard ground system wire is AWG solid bare
soft drawn.  I think engineering firms like everything done the same
way from one site to the next to reduce variables for a full proof and
get a DA dialed in to the licensed pattern.

Why the teflon insulation?

73

Rob
K5UJ
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