[time-nuts] For sale: HP 8405A RF Vector Voltmeter pick-up only - Menlo Park, CA

[Bob L.]

Hi folks,

I'm offering a late production HP 8405A RF Vector Voltmeter in fine
operating and cosmetic condition:  $275 cash, pick-up only in Menlo Park, CA

The 8405A is for cash sale, pick-up only near the intersection of 101 and
Marsh RoadÂ
 about half way between San Francisco and San Jose. Sorry, but no
exceptions.

 

I have the 8405A posted here with photos:
https://forums.qrz.com/index.php?threads/hp-8405a-rf-vector-voltmeter.765676
/

Loads more detail available on the web at links listed below.

 

My main use for the 8405A was to measure phase drift between clocks as the
frequencies would slowly drift one relative to another. At one point I had a
reference 10 MHz clock on the 8405A A channel and up to 7 additional clocks
switched onto the B channel. The 8405A gave a DC voltage proportional to the
phase difference in degrees.

I was using an HP 34970A data acquisition unit with an HP 34905A dual 4:1 RF
plug-in module to select one of 7 clock inputs for the B channel. The 34970A
chassis includes an internal DVM that I used to measure the DC voltage
corresponding to phase difference. All this under computer control.

 

Details on the 8405A can be found in an HP Journal article here:

https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1966-05.pdf

 

Operating and Service Manual:

http://www.k0to.us/HAM/Articles/HP 8405A Operating and Service Manual.pdf

 

The Agilent HP 8405A Vector voltmeter measures voltage vectors described by
both magnitude and phase. This capability makes the Agilent HP 8405A a
unique instrument for about any design and test application in the frequency
range 1 to 1000 MHz.

 

Features:

•             Measures voltage vectors described by both magnitude and phase

•             Ideal for almost any design and test application in the
frequency range of 1 to 1000 MHz

•             Measurement capabilities include insertion loss and group
delay of passband-filters and other transmission devices, gain and phase
margin of amplifiers, complex impedance of mixers, antennas, etc.

•             Two channels allow for ratio measurements and phase difference
between the two channels

•             Gain or loss in excess of 90 dB and phase measurements with
0.1° resolution over a 360° phase range are possible

 

Amplitude of the A and B channels are reading within a dB or so of each
other between 1 MHz and 1000 MHz. An image at the QRZ site posting shows the
8405A channel A response compared to an Advantest R3463 spectrum analyzer. I
made an attempt to match the cable lengths and losses to the analyzer and
8405A for a fair comparison.

 

The 8405A will include two probe to BNC adapters and two Mini-Circuits 20-dB
BNC attenuators as shown in the photos. I've keep these on the probes full
time except in very rare cases when I needed direct access to the probe
tips. The combination of an adaptor and attenuator does a nice job
protecting the probe input circuits.

 

Many thanks for your interest!

Bob 

bobhome    <at>   pacbell   <dot>   net



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