Richard Clark wrote in
:

On Tue, 27 Feb 2007 21:14:38 GMT, Owen Duffy wrote:

This is not contending nor contention and is content only for a non
sequitur. The line following a tuner exhibits considerable loss
(poor efficiency) that can only occur on the basis of power and
mismatch. You yourself offered in other correspondence that it
exceeds cable attenuation specifications found only in a matching
condition. To

I am being picky, but "it *may* exceed cable attenuation
specifications found only in a matching condition, it may also be
lower".

Hi Owen,

Lower? That is rather astonishing in light of responding to my
comment.

If I said it
as you stated, I made an error. The common statement (and I have no
doubt made it) that VSWR exacerbates line loss is actually wrong in
the general case. (Having Googled my own web site I see one statement
along those lines which needs further qualification!)

This is even more astonishing. Irrespective of you being the source,
why inject this confusing comment? SWR always exacerbates line loss!
Give me any normal line attenuation and SWR at the load, and I will
tell you exactly how much additional loss will occur. There's a
general solution for you.

Something tells me that your comments are based on a confusion between
the power loss of a cable, and its mismatch loss. They are not the
same thing although they are usually tightly twined in discussion. You
later exhibit a confusion between a conjugate match and an impedance
match. They are not the same thing either. The confusion on both
these points have abounded in this group in past "debates."

Just to deal with this issue, line loss under VSWR, which at first seems
a side issue, but it illustrates one of the problems of a "power
perspective" in analysing a transmission line.

By "line loss" I mean the ratio of power at the load end of the line to
power at the source end of the line, not "forward power" or "reflected
power", but the average rate of flow of energy at those points.

So, to your challenge:

The problem is 1m of Belden 8262 (RG58C/U type) at 3.5MHz with three
loads, 50+j0, 5+j0, and 500+j0.

The loss for 50+j0 load is 0.025dB (equivalent to the Matched Line Loss).

What Line Loss to you get for the other two cases?

(I make it 0.24dB for 5+j0, and 0.014 for 500+j0.)

Owen