[Antennas] Need a bit of wire advice

Thu, 07 Feb 2002 20:42:48 -0500

To be technically accurate the 'crud' will have an impact on antenna
performance.

Serious copper oxide or copper sulfide build up on the surface increases
the RF resistance of the wire due to effects caused by 'skin effect'.
The increased rf [ac] resistance will contribute to antenna efficiency
by decreasing it. Remember your antenna has two resistive terms; 1)
radiation resistance, and 2) ohmic [loss] resistance.

A judgment is that even with significant 'crud' the decrease in
efficiency is not noticeable in amateur communications i.e. typically
less than 1 dB.  However, for rf systems engineering where system
specifications have to be met ... well that's a different story.

73, Dave, W1MCE
Manager, MK21 Antenna Range, retired

[email protected] wrote:
> 
> Hi Gang,
> I have a lot of 14 GA unsulated wire for an antenna that is ready to go up.
> But after looking at the 15-M antenna that has only been out in the weather
> for a summer it sure loks cruddy.
> I get this bare strand wire for free but how will all the built up crud
> affect it?
> RS has # 14 insulated wire in a 100 foot spool at $21.95 and on the spool it
> says indoor/outdoor.
> The color is brown and not as easy to spot.
> So use the bare wire or insulated?
> Thanks
> Bob
> WA2HOQrp <tm>
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