[R-390] HP Spectrum Analyzer

[2002tii]

Perry wrote:

>HP 3585A is certainly the way to go if one has a spare kilo buck! In 
>the more affordable range is the HP 141 series.   They are plentiful 
>and can be found complete and working in the $400 range.  But 
>shipping can be high. There are a number of others you might also 
>want to consider.  The HP 181 while not as prevalent as the 141 
>series if often reasonably priced. I think you should also consider 
>units made by Tektronix. They have the 491 and 492 stand alone 
>units.  They also have a 7L12 plug in for the 7000 series of scopes.

One shouldn't have to pay $1000 for a 3585A, although as Perry noted, 
asking prices vary wildly.

One thing to think about carefully when buying a SA is the minimum IF 
bandwidth.  A lot of analyzers don't have the narrow bandwidth IFs 
you need to clearly separate signals that are near each other.  For 
scanning a whole band, 100-300 Hz is best, and 1 kHz will do in a 
pinch.  For looking at 20 kHz of spectrum, 10-30 Hz is much 
better.  And for looking at one signal in a 2-10 kHz bandwidth, 3 Hz 
is very useful.  Also, older analyzers are often not well calibrated 
as to frequency, so you end up spending a lot of time and energy 
doing that manually with a generator and counter.  The 3585 reads 
accurately to 0.1 Hz.  It also has a tracking generator, which is 
invaluable for design, or characterizing filters, or any number of 
other things.

It's all about what you need it to do.  And while you're thinking 
about that, also try to imagine things you might be able to do with a 
SA that you haven't thought about yet, and what cababilities those 
would require.

With any of them, you want a CRT that doesn't have a million miles on 
it.  The newer analyzers typically keep track of on hours and on-off 
cycles.  It pays to familiarize oneself with the operators' and 
service manuals of the models under consideration, so one can give 
the seller step-by-step instructions to get this information and run 
basic diagnostics.

Best regards,

Don