Wes Stewart wrote:
On Thu, 04 May 2006 11:49:37 -0700, Roy Lewallen
wrote:


Thanks for the clarification.

The HP4805a isn't an impedance meter. It's a vector voltmeter, which
measures voltage amplitude and phase. As you know, it requires external
directional couplers to measure impedance. (Or you could use current
measurements using current probes in addition to the voltage measurements.)


Whoa, hold on, wait a minute or as we are now required to say in
Southern Arizona, Alto Amigo!

I think that Dan made a typo and meant to say "HP-8415", which is a
vector impedance meter that does use a constant current r-f source and
a voltage measurement to determine impedance.

It's a handy instrument for probing circuits, but it has a limited
higher frequency limit of 108 MHz.

There is one he

http://cgi.ebay.com/HP-4815A-RF-VECT...cmdZVi ewItem

but without the probe, which makes it totally useless.

[snip]


I think the OP really means 8405 which is a VVM. I think he swapped the
first two numbers.

He can tell us if I'm wrong.

Cheers,
John