[time-nuts] Which HP Frequency Counter?

[Ulrich Bangert]

Jean-Christophe,

I would like to second Dan's opinion. Despite of owning some HP counters
and a SR620 from Stanford Research i regulary use my good old RACAL DANA
counter. The model 1992 is a standard even at European based surplus
dealers. An even better buy than the 1992 is the not so often seen model
1996 for example at

http://www.rainer-foertig.de/Zaehler.htm

because it has an increased number of measurement facilities. The
trouble with the pushbutton switches is the same with this model. RACAL
DANA has used push buttons over a period where the color ingredients of
the switch body would gas out over the time and ruin the elasticity of
the plastic part closing the switch contact. This is very easy to
diagnose: If you press the button and it does not "come back" you have a
ruined pushbutton that must be exchanged. 

I did already exchange the complete set of of buttons on my 1996 for two
times. You can imagine that I would not have done this if the device
itself were bad. The last switches that i built in are completely white
and do not have additional color ingredients. This seems to have sold
the problem!

Best regards
Ulrich Bangert

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Dan Rae
> Gesendet: Samstag, 8. Marz 2008 18:36
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] Which HP Frequency Counter?
> 
> 
> Jean-Christophe Deschamps wrote:
> 
> >Dear group,
> >
> >I consider buying a used lab frequency counter / timer --preferably
> >HP/Agilent-- covering from few mHz to perhaps 400 MHz.  I'm worried 
> >that models handling high frequencies seem to be limited to 
> under 100 
> >mV input signal max. I don't want to destroy an input channel each 
> >other day when calibrating/repairing some instrument.  Also 
> are there 
> >instruments with high impedance input? 50 Ohm is not quite right for 
> >investigation in the guts of most designs.
> >
> Jean-Christophe,
> 
> I know you said HP, but the one instrument that I have on my 
> bench and 
> use all the time that is not by HP is a Racal-Dana 1992 counter.
> 
> It has three inputs, the A input can be set to 1 MegOhm impedance and 
> will count up to 160 MHz at good sensitivity, 50 Ohm loads and 
> attenuators and filters also available.  The C input goes to 
> 1.3 GHz, 50 
> Ohm only.  The A and B inputs can be used for phase 
> comparisons.  Most 
> of them have a very good quality Ovened timebase, Option 04E.
> 
> There are a lot available in the US and not so many in Europe, prices 
> for what they are seem very reasonable; in the US $200 to 
> $300, working.
> 
> Some have trouble with the push button switches, these can be 
> replaced, 
> but it is a big job to do, there are a lot.  Apart from that 
> I know of 
> no other common failure modes.  Not a lot of other components inside 
> that cannot be found easily enough.
> 
> Manuals are freely available.  And it is quiet.  No fan noise.  My HP 
> counter sits in the garage...
> 
> Good luck, 
> 
> Dan
> 
> 
> 
> 
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