[time-nuts] Test equipment

Dick Moore richiem at hughes.net
Thu Jan 21 23:13:40 UTC 2010


Hi, John -- having both a couple of GPSDOs and an HP 5345A, I'm going to offer the (perhaps) minority opinion that you not drive the external clock input of the 5345 from the 10MHz  output of a GPSDO. I was lucky enough to get a 5345 with a really good, well-aged 10811A OCXO in it, which has proven to be very, very stable. I do use my Trimble TBolt to check the 5345 every once in a while, with the 5345 averaging over the longest time it offers; then I do the same thing with my other GPSDO; then I scratch my head and see how the three of them compare. Adjusting the 5345 is a time-consuming, frustrating, and essentially pointless operation, since there is no "fine-tuning" of the 10811's output. Better to just log the variances and make compensating calculations for critical measurements of time or frequency. 

As to other gear, maybe an HP/Agilent 34401A or the equivalent Fluke or Keithley 6.x digit DMM would be useful -- older HP DMMsa with 6+ digit resolution come up for peanuts on auction sites all the time, and a 3456A for example is a very good, very versatile instrument once it's cal'd.

My 2 cents.

Dick Moore

> Message: 2
> Date: Thu, 21 Jan 2010 13:35:22 -0500
> From: John Foege <john.foege at gmail.com>
> Subject: [time-nuts] Test Equipment
> To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Message-ID:
> 	<888d55281001211035tfa48d5ew5e36acf584cc54ea at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
> 
> I realize that this e-mail is somewhat off topic, however, I also
> believe that I will get some of the best answers from the members of
> this list:
> 
> I have recently started to build an electronics lab, and am currently
> trying to acquire test and general equipment for my little basement
> workshop of horrors. So far, being on a limited budget, I have
> acquired a Tek 2465A in good working order, a Fluke 1953A counter, and
> my little gem (ok not quite so little) HP5345A with the 4-ghz freq
> converter plugin w/ opt 11 & 12.
> 
> I'd just like to ask everyone what they would be, if they were in my
> shoes, attempting to acquire. Unforunately, however, I am just out of
> engineering school and not working with much of a budget here. I'd
> kill to have all the fancy gear some of you nuts have.
> 
> I'd really love a DSO instead of the Tek 2465A I have. I'd kill for a
> good spectrum analyzer or VNA etc.
> 
> Any suggestions on what I should acquire and/or suggestions for
> economical equipment that I should make that is a must have? I am a
> good DIYer when it comes to building equipment, so often I attempt to
> build that which I cannot afford.
> 
> I appreciate everyone's' opinions in advance. Thank you.
> 
> Sincerely,
> 
> John Foege
> KB1FSX
> starving-engineer!





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