Topband: radial wire size

[donovanf at starpower.net]

Hi Jorge, 


Bill is almost correct, in most soils mechanical durability is the only 
consideration for long term durability of copper wire, but out of sight 
out of mind can be a big problem for radial systems in at least two cases. 


Galvanic corrosion will damage a buried radial system i f small (or large!) 
electrical currents flow from the shield of your coaxial cable into your radial 
system. Of course, small diameter wire will fail more quickly than heavier 
wire. This is not a trivial consideration because in many installations the 
buried radial system has significantly lower ground resistance than any 
other ground in your home or in your station. You can determine if this is a 
problem in your installation by using a milliammeter (or a common VOM) 
to check for shield current. 


Corrosive soils may damage a buried radial system. Fortunately most soils 
are not corrosive for copper but there are important exceptions, some 
examples are: 
- soils with large quantities of organic matter, 
- poorly drained soils such as wetlands, 
- soils with a history of heavy agricultural use with farm animals or fertilizers 
- soils containing materials such as cinders or cinder blocks. 


73 
Frank 
W3LPL 







----- Original Message -----

From: "Bill Wichers" <billw at waveform.net> 
To: "Jorge Diez - CX6VM" <cx6vm.jorge at gmail.com>, "topband" <topband at contesting.com> 
Sent: Wednesday, April 15, 2015 2:27:01 PM 
Subject: Re: Topband: radial wire size 

The only real difference when using reasonable-gauge sizes is in physical durability. Electrically it makes little difference since you effectively have a large number of radials in parallel so each one carries only a relatively small percentage of the overall current in the system. 

I use 18 gauge bare solid copper on my radials. I use that size since I consider it a practical minimum in terms of physical durability and I can get it for around $50/thousand feet from my supplier (although they have a 5,000 foot minimum order). I've had some 60+ radials in place for about 4-5 years without any problems. Once the copper turns a dull-brown color after the first season it's almost impossible to see on the ground. 

A lot of people use 14 gauge since that's a commonly available size for building wire in the US. It's easy to get through "regular" (hardware store) channels and it's strong. There isn't really any electrical advantage to the heavier wire -- you won't notice any difference in performance. 

I think you'll be fine with the #17 wire you have access to. Save the money on the smaller radial wire and spend it somewhere else where it will make more difference in your overall antenna system. 

-Bill 

> Hello 
> 
> 
> 
> Thinking in a 4 SQ, buried radials, 60 or more on each vertical 
> 
> 
> 
> What is the difference in performance between installing radial wire size 
> #14 (2.08 mm2) or #17 (1.04 mm2) ? 
> 
> 
> 
> #14 is the size that DXE sell, so I think is a good size for radials. But what about 
> #17? 
> 
> 
> 
> In $$$ is the half J, so want to know what I am loosing in performance, if any 
> 
> 
> 
> Thanks in advance 
> 
> 
> 
> 73, 
> 
> Jorge 
> 
> CX6VM/CW5W 
> 
> 
> 
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