"Frank" wrote in message
news:6Pnlf.138047$y_1.50980@edtnps89...


The type of coupler I am thinking of is indeed where the coupling lines
for
forward and reflected are in the same physical region. The point I was
making refers particularly to the HP 778D; where it is specified in:
http://cp.literature.agilent.com/lit.../5952-8133.pdf
"Data can be read from the two meters of the vector voltmeter and
transferred directly to a Smith Chart". Indicating that there is no
significant phase error over the nominal bandwidth of the coupler.

The old vector voltmeter has a phase offset ability to compensate.


Just read Wes' comments on the line stretcher on the above pdf. I must
admit I also wondered about that, but assume it is intended as a cal
adjustment for a short/open standard.

See my previous post on this. It IS used to get both samples "At the
measurement plane."

73, Steve, K,9.D;C'I