Re: NEC-LIST: Copper oxide.

At 7:35 AM -0800 1/10/04, Jim Lux wrote:
>Copper Oxide is a fairly good insulator. The layer is thin, typically. It
>probably wouldn't have a huge effect. What really bites you is if the
>conductor is covered with a thick layer of something resistive or lossy.

Two questions:

1. Have measurement data been published, showing whether stranded
copper wire with various degrees of surface oxididation/corrosion is
more, or less, lossy than solid copper wire of the same gauge, at HF?

In wire antennas for HF I use finely stranded (copper) wire because
it does not fatigue and break as quickly as solid wire does. I use
_insulated_ wire, and I seal the ends of the insulation at splices
etc., in order to keep the surfaces of the strands from
oxidizing/corroding. (Acid rain is an issue where I live.) However,
it has occurred to me that if each strand had an effectively
insulating coating, then I'd have something akin to Litz wire, and
the loss at HF would be less than if the strands were clean.

Mostly I use such thick (low-number-gauge) wire that its loss is
trivial, so my question is mainly academic; but I _am_ an academic.
:-) [For balloon-supported HF antennas I use very fine Litz wire,
which can't be beat for RF conductance per unit weight.]

2. The fact that copper oxide (and possibly other copper corrosion
products; I don't know) can be semiconducting raises the possibility
that stranded wire in a high-power transmitting antenna could
generate harmonics and intermodulation products. What has been
published about _this_ possibility?

Tnx es 73 de Chuck, W1HIS

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