"Walter Maxwell" wrote in message
news
On Sat, 21 Aug 2004 00:30:48 GMT, "The other John Smith"

wrote:

Is it possible to recall what you were measuring, and what the setup was
when
yo;u obtained the negative resistance indications, such that you could
repeat
it just to humor me?


Okay, I just found a tiny note on a piece of paper which says:

"B1/A1 = .90 at 180 degrees reference (shorted)"

and

"16 and 1/2 inches of RG58A (shorted) gives B2=0.74, A2=0.81, at -110
degrees"


This works out to -0.56 - 35i. Unfortunately, my note does not indicate the
nature of the load.

It looks like the real part goes negative if A1B2/A2B1 1. Yes, I think I
see it now. If the reflection coefficient is greater than one, that
indicates more is being reflected than is being supplied -- meaning I have a
source at the supposedly shorted end of the coax. Ah ha! I am now very
confident that I either misread the instruments or misadjusted something.

Anyway, I think I have the answer I was seeking. Except under extraordinary
circumstances, I should never get a negative real part answer.

My thanks to the contributors of this thread. It sure helps to have others
to talk things over with.

John