"Cecil Moore" wrote in message
et...
Wes Stewart wrote:
The VVM probes are comprised of a quad diode sampling bridge followed
by an FET amplifier. They are nominally coaxial, although without the
BNC adapters, they have an exposed pin (very delicate) and at lower
frequencies they can be used much as a high impedance scope probe is
used.

Thanks, Wes. When you say "lower frequencies", does that include
4 MHz?

The instrument uses a phase-locked oscillator to drive the samplers
with the "A" probe being the reference. One meter can be switched to
display the amplitude of either channel and the second meter reads the
phase difference between them.

I was planning to use toroidal pickups and a Lissajous figure
for the phase measurement. Did you know "Lissajous figure"
is described in my 1957 ARRL Handbook but not in my 2000
ARRL Handbook?

My main concern is how to ensure there are no reflections
present during the measurement. I need to put the 75m
bugcatcher coil in an RF loop where current is flowing
in only one direction. That's easy to draw on paper but
I'm concerned about it. How would you set it up?
--
73, Cecil http://www.qsl.net/w5dxp

Hi Cecil

I have the Technical Manual for the HP 8405 (36 MB) and could send it to
you with "Usendit" or "Skype".

Jerry