"Larry Benko" wrote in message
...
As I am getting closer to retirement I have been thinking about buying a
used spectrum analyzer since I will not have access to one at work.
Unfortunately I am not familiar with all the models from say 5 to 15 years
ago. Is there a good reference describing the different HP/Agilent,
Tektronix, etc. models and which are good and which to avoid. A quick
look on Ebay shows HP 4195A, 8561E, 8562A, 8562B, 8563E,8565A,
8568B,8569B, 8591E, 8593E, and 8594E. Similarly for Tektronix 492P, 494P,
495P, 495A, and 2755P. Is there some kind of a used buyers guide
available. I understand spectrum analyzers at a moderate level and
realize the differences between frequency range, external mixers, dynamic
range, bandwidth etc. but finding the specs in a manner that makes them
comparable is hard. Thanks for any advice.
73, Larry W0QE
I have an HP-141T, with a full set of the plug-ins. Buying one of these on
eBay may be risky, since so many analyzers get abused by incompetent users.
I would demand a right-of-return guaranty, and better yet, a personal
interface with the seller.
Technically, the 141 system is great, top-of-the-line gear for 1975. g But
it has no automation to guide and help you, no FFT, no digital output, no
way to archive data other than a Polaroid camera hood. (Actually, you can
take a fairly decent digital camera picture of the display. And yes, there
is an interface for an X/Y analog plotter, but who has one of those plotters
anyway?) You might want to get a 141 for it's analog quality, and then do a
digital interface project on your own.
Don't select an HP-4195A for a spectrum analyzer. It doesn't have the full
SA capabilities, although it triples as a SA, network analyzer and an
impedance analyzer. You might find it much more suited to be a NA (up to 500
MHz) than anything else. It does have a 3.5" floppy, but the format is HP
LIF, not DOS, so the data is not very transportable. It has an IEEE-488 I/O,
so you can interface it to a PC. It's also god-awful heavy!
An 8562A is sweet, because it is also a fine SA, and it will go up to 18
GHz, and then will interface with the HP-11970(?) microwave harmonic mixer
series, to let you go up to 96 GHz or so. It's also a lot more portable; you
can carry one for over 100 meters before your fingers get numb.
I had a Tek 49x at one time; I never liked it. Subjective, true. I'd take
one for free.
I always considered the HP-859x series to be the cheaper descendants of the
856x series. Still, nice instruments, but maybe not yet cheap enough for
retirees.
The HP-8566B was HP's grand killer SA, with the 8568 being the lesser
capable sister. If you could find an 8566B at a price you could pay, that
would be great. The pinnacle for 1987. You can carry an 856x about two feet.
Be aware that all of the instruments we have been talking about are full of
proprietary modules that are no longer in the parts pipeline. The CRT's are
a real problem; the only place to get another one is from a parts unit. (OK,
maybe somebody has some new ones, in the box, right next to their pile of
unbuilt Heathkits!) Although the HP units were all top commercial quality,
something will eventually fail, and Radio Shack won't be much help. OTOH, a
non-abused HP could easily outlive the average retiree. g
--
Ed
WB6WSN
El Cajon, CA USA
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