"JGBOYLES" wrote in message
...
I'm interested in measuring the velocity factor of some coax I have (more
of
an exercise than necessity). In order to do this, the MFJ-259 Operations
manual states that the "stub" to be measured should be attached with a
50-ohm noninductive resistor
Hi Jason, I just looked at the manual for the 259 and the 259B and it did
not
mention a 50 ohm resistor in the velocity factor section. With both
instruments you measure the electrical length of the coax and compare to
the
physical length to obtain velocity factor. It is a bit easier with a 259B
using the "distance to fault" function. The coax can be open or shorted
(far
end) during measurement. No resistor needed as far as I can tell.
73 Gary N4AST
Gary, the manual indicates to 'Set up the line to measure 1/4 wave stubs as
in the section on "Testing and Tuning Stubs"'... In that section, it
requires a 50-ohm resistor in series to the center conductor. Perhaps, the
resistor isn't needed to measure VF? This is really a poorly written
manual-- while it acknowledges possibilities, it really isn't clear in its
procedures :-/
Let me know what you think. Maybe you're right and the resistor isn't
needed for VF.
Thanks,
Jason
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