[time-nuts] Inexpensive Alternative to a 5120A

Bob Stewart bob at evoria.net
Fri Oct 7 13:20:41 EDT 2016

Hi Randal,
I've got a bad cold, so I can only hope this response is rational.
To begin with, you need some sort of Time Interval Counter (TIC), as well as some way to get the measurements from it into your computer.  Once you get that, then you get a free copy of John Miles' indispensable Timelab software and have at it.
A beginner setup might consist of an HP 5335A, which can be found cheaply, and a GPIB adapter.  Be sure to get a 5335A with the high stability OCXO; i.e. the venerable HP 10811.  You can find both on ebay, but the usual cautions apply.  Personally, I prefer the Prologix Ethernet GPIB adapter.  It's pricey at about $200, but it's the easiest for mere mortals to interface to with custom programs that you may be tempted to write.
If you want to get a bit better than that, then you'll probably go with an HP 5370A with a 10811.  Other companies make good TICs, as well.  At some point you'll probably want to get a better standard than the 10811 in your counter, so you'll consider either a Rubidium standard or a Cesium standard.  Personally, I'd avoid the FE-5680s on ebay, as they're not as stable as you'd expect them to be.  But, other people may disagree.  Cesium standards aren't cheap - unless you happen to make the score of a lifetime as another time-nut did with a PRS-45A.
You can also use a GPSDO as a reference.  I sell a new one, and you can find good surplus units on ebay at various prices.  Different GPSDOs will have different qualities.  They all suffer from to extent from ionospheric drift.  Older units with older receivers probably have the most, but I'm not an expert on GPSDO selection.
So, with all that said, start with the cheapest you can afford, and then decide whether you really want to get into serious time-nuttery.  It's not an inexpensive hobby, even at the low end.  But it's probably cheaper than a diet of loose women and beer!

Bob - AE6RV


      From: Cube Central <cubecentral at gmail.com>
 To: 'Discussion of precise time and frequency measurement' <time-nuts at febo.com> 
 Sent: Friday, October 7, 2016 11:52 AM
 Subject: [time-nuts] Inexpensive Alternative to a 5120A
I saw that someone was using one of these: http://www.microsemi.com/products/timing-synchronization-systems/test-measurement/test-sets/5120a

...and the more I looked at it, the more I wanted one.  However, I couldn't get a price for one, but only quotes.  This can only mean that they are really expensive and out of reach of mere mortal novice time-nut like myself.

Is there an alternative that someone could point me to that would cost only a couple hundred rather than (what I expect) is a couple thousand?  How would I go about gathering the data needed for these nifty ADEV graphs I see floating about in here?

Could there be a kit or something that I can plug into a PC?  I really don't even know where to start looking?

Thanks - in advance - for any suggestions!

    -Randal R.
        (at CubeCentral)

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