[Elecraft] Signal / RF generator

[Jack Smith]

Pair of HP 8657A synthesized generators 100 KHz - 1024 MHz
Pair of HP 8640B analog w/ lock generators, one with internal doubler 
(1024 MHz) and reverse power protection
Panasonic VP8191A synthesized 100 KHz - 135 MHz

8640B is quite plentiful, and when properly working is  very hard to 
beat for phase noise and all around use. However, these are 30+ years 
old and are notorious for bad switches which are works of art involving 
circular PCB and spring fingers, custom made by HP.  If you are 
mechanically inclined and have the patience to work on them, the 
switches can be repaired.

HP made several "moderately priced" synthesized generators that show up 
frequently, 8656A is not recommended as the specs are marginal and they 
use a mechanical (relay) controlled attenuator that may be worn out if 
the particular unit you buy was exercised enough.

HP8657A and B. I have a pair of A units and they are fine, if you 
understand their limits. The main limit is that they have spurious 
products. Some nearby the carrier from 120 Hz noise. Others further 
away, such as at integer multiples of 1 MHz. Phase noise is so-so. B 
units are better  than A units. Difficult to use if you want to test 
close in IP because phase noise and 120 Hz spurs and discrete 
synthesizer spurs can interfere with your measurements.

HP8642A. Don't have one but been thinking about buying a pair. Supposed 
to be major improvement over  the 8657A and B in terms of phase noise 
and synthesizer spurs. Appear on E-bay in the $1K to $2.5K range.

Anyone with hands-on experience with the 8642A care to comment?

If you don't mind the inconvenience, HP generators with the RF output 
and modulation input appearing only on the rear panel (used in computer 
controlled arrangements) are generally cheaper than ones with the more 
normal front panel connectors.

Jack K8ZOA
www.cliftonlaboratories.com


On 1/31/2010 1:58 PM, n0jrn wrote:
> Gang:              Considering the purchase of a signal generator for
> aligning the projects in the shack.
>
> Looking on e-bay shows several low cost options.  Most are pretty old and
> likely in need of some work.
>
> SO figure I would query the group to see what everyone else is using.
>
> IF your using a signal / RF generator,  what brand, model and options are
> you using ???
>
> Was there a reason you choice the unit you have over some other ????
>
> Just curious
>
> 73         Jerry             N0JRN
>
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