[TowerTalk] tuners and power rating

Paul Christensen w9ac at arrl.net
Wed Dec 1 05:44:42 PST 2010


> I think calling this situation "mismatch gain" would be
> confusing as heck to some people, but if we insist on calculating the
> "additional loss due to line mismatch," this is exactly what happens.

I see no issues keeping it like it is.  It's an anomaly with short 
wavelength sections of line.  More than anything, I think it helps as a 
learning tool.  You can take all the printed reference materials on 
transmission lines and combined, they are no substitute for playing "what 
if" analysis with a transmission line calculator.

The additional loss attributed to a mismatch is still relevant once SWR 
becomes part of the loss.  In the 10 ft. examples we've been using, that 
occurs when the line get to roughly 40 degrees in length.  When we approach 
1/4 wave, loss due to SWR becomes equal in loss to I-squared-R loss.  I 
think that's was one of Steve's points in that the additional loss 
attributed to SWR needs some clarification in the footnotes o be completely 
accurate.

Paul, W9AC




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