On Fri, 26 Nov 2004 16:12:34 GMT, (Robert Lay
W9DMK) wrote:

|On Thu, 25 Nov 2004 20:51:16 -0700, Wes Stewart
|wrote:
|
|On Thu, 25 Nov 2004 20:20:32 GMT, (Robert Lay
|W9DMK) wrote:
|
|Bob,
|
|You might want to look at this paper:
|
|http://users.triconet.org/wesandlinda/AIEE_High_Swr.pdf
|
|
|Dear Wes,
|
|I have downloaded the pdf file and printed it out. It's tough reading.

Yes. But the ITT Reference Data For Radio Engineers uses this paper
as a reference.

If you have Mathcad, a sheet that implements some of the equations was
included as a reference in my Balanced Transmission line paper.

http://users.triconet.org/wesandlinda/LineCalc.mcd


|I hope that MacAlpine agrees with what Dave and Richard are telling
|me, because their responses seem to be correct and are exactly what I
|was afraid of - that I've been sucked into another example of the
|strange terminology used to describe "losses".
|
|I have always thought of "loss" as a conversion to another form of
|energy (typically heat energy) which is lost from the system.
|Apparently, the kind of "loss" being described in the example that I
|gave is not a loss at all.

Yes it is. A simple-minded way of looking at it is if the SWR is
greater than unity then increased current is flowing in the line. The
line has resistive loss, so the I^2*R loss increases. The current
isn't constant (there is a current standing ratio, ISWR, just like a
VSWR) so there are peaks and valleys in the current and as you have
figured out, the longer the line and the higher its nominal loss, the
lower the ISWR is at the line input.

So the loss per unit length is non-linear and varies with distance
from the mismatch, but it is a real dissipative loss.

For those interested in the loss in the shorted or open stub case,
maybe this will be of interest:

http://users.triconet.org/wesandlind...ching_Loss.pdf