[TowerTalk] aluminum radials Re: Ground wire impedance

[Jim Lux]

At 12:51 PM 7/13/2006, kb0fhp at comcast.net wrote:
>Trouble with aluminum, is that it oxidizes, and causes an oxide buildup at 
>the connection.  This increases the resistance.  At least for home 
>electrical wiring, special connections have to be made.  But for radials, 
>it will probably work....as long as a nice tight mechanical connection to 
>cut thu the oxide film is provided....

Or, join all the aluminum radials with welding/hard solder.

But this is an interesting point..  Aluminum is a LOT cheaper than copper, 
and if you're in a "low labor cost" situation where material cost 
dominates, you could put a lot more aluminum in the ground than copper, 
thereby getting lower overall loss.

I note that most gain antennas are made of aluminum, not copper.

The corrosion issue is interesting.  It's going to be highly soil chemistry 
dependent.  Could one do some sort of electrical protection (sacrificial 
electrodes, etc.)?  No matter how you look at it, you're probably going to 
be doing some sort of maintenance cost vs installation cost tradeoff, but 
that's a classic engineering thing.