I remember when the 8642 came out, it was supposed to replace the
8640. But there are so many of them out there (or there were) that HP
had to keep the 8640s supported for some time. Ditto for the 8642. A
lot of their products these days get 5 years max support after being
discontinued before you cannot get parts/manuals.
I used a 8644 last summer on an experiement, where I needed to ramp
the amplitude, AM, while it was being pulsed. It is a very complex
all digital box. I discovered a glitch which occured when it was
ramping as certain attenuators were switching, which would long pulse
the output. This in turn kept tripping off my 500 kW 200 MHz
amplifier, which it was driving (through a solid state amp and
another tetrode). The 8644 takes two people to move it.
I almost bought an 8643 last year on EPAY, but it had a dent in the
front so I passed. I think they went for about $1500. If that machine
breaks, you are screwed, nothing user servicable, except for module
replacements $$$.
73
John
K5PRO
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|