> thinking of making a RF ground/radial on the roof. I have been given
> access to a "free" supply of 1/2" copper tube, ex water heating. I
> have read that it is better to have a flat section rather than a round
> section for the ground/radials. I am thinking of "flattening" the tube
> which would give approx 3/4" wide copper strip.
Hi George,
I think "Ask the Doctor", in QST, gave an incorrect answer to the
very same question you are asking. I *think* they said if you
flattened the conductor, the resistance would decrease, but I only
scanned it quickly and can't recall the issue to look back at it.
The lowest loss resistance would come from a round conductor. If
you flatten it, current bunches at the edges and the losses go up.
There is less-even current distribution in a flat conductor with the
same surface area as a round conductor. Of course if you pounded
it into very wide thin strips, you could increase the total surface
area...but that would take some real pounding. Better to pound
brass instead.
For what you are doing, none of this makes any difference. You
could use #18 wire, or something as fat as your thumb, and things
would hardly change. That's because current in each radial is
small, and the radials are in "parallel" at the common point. The
number of radials is much more important than how thick they are.
73, Tom W8JI
W8JI@contesting.com
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