[TowerTalk] RF resistance of copper oxides

Jim Thomson jim.thom at telus.net
Fri Oct 14 10:50:37 EDT 2016

###  KM1H used cu tubing for his .25 wave strip lines in his 144 mhz tube amp.   The cu tubing  has since turned green.   Amp was built
a long time ago.   Zero effect on BW or PO or gain.  Amp was built > 25 yrs ago.    As long as the terminations at each end are good, you wont have any issues. 
Its when you have bad connections from corrosion or oxidization that u start having problems 

Jim  VE7RF 

From: dfaklis at frontiernet.net 
Sent: Friday, October 14, 2016 7:30 AM
To: towertalk at contesting.com ; rxdesign at ssvecnet.com ; jim.thom at telus.net 
Subject: RF resistance of copper oxides

Here's some additional reading on this topic.  We typically decide to neglect the effect, but it is non-zero.




73, Dean, NW2K


...that the tarnish would be more like insulation and the current would simply flow through the copper below (low resistance path) ...

...Dull and tarnished has zero effect...The rf current simply travels beneath the tarnish.

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