[time-nuts] Inexpensive Alternative to a 5120A

Cube Central cubecentral at gmail.com
Fri Oct 7 15:03:09 EDT 2016


Thanks again, Bob.  I've just ordered the controller you suggested.  No wonder I was running into a mental block, as the port on the back of the 5335A counter says "HP IB" and there was all this talk of "GPIB" and I simply didn't put 2 and 2 together.

I gather that the Ethernet one will work over a standard LAN and that the Timelab software will have no issue finding it (once configured?)  I should - and am about to - start reading on how to set up that controller.  I was thinking that the USB one might be more direct into a neighboring computer, but not knowing anything about it, will go with your suggestion.

This certainly opens up many new avenues for me to continue learning as I am ready for this next step to bring a PC to bear on measurements.  I am glad that I had the accidental foresight to get the correct TIC!  Thanks again and any further suggestions on where to start (especially what to plug into what as described below which I found helpful) is greatly appreciated.  

    -Randal R.
        (at CubeCentral)

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Bob Stewart
Sent: Friday, 07 October, 2016 12:43
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Subject: Re: [time-nuts] Inexpensive Alternative to a 5120A

Here's the one I recommend:  http://prologix.biz/gpib-ethernet-controller.html

No, it's not a $35 adapter, but IMO it's worth every dime because 1) it's ethernet and not USB and 2) I can write C programs to interface it without knowing anything about the underlying GPIB protocol.  Also, Timelab talks to it just fine.   (Disclaimer:  I have no financial or other relationship with the Prologix people.)

For your timing tests, you'll probably want to connect a cable from the 10MHz TIME BASE out in the back to channel B in the front.  Send the 1PPS to Channel A and use Function Time A->B.  To measure two 10MHz signals, connect them to A and B and route the 1PPS signal to the arming input on the back.

Bob
 -----------------------------------------------------------------
AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info

      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 1:32 PM
 Subject: Re: [time-nuts] Inexpensive Alternative to a 5120A
   
Thanks Bob, I hope your cold improves, and I thank you for that answer.  

As I happen to have a HP 5335A and I think it has the options 10 and 30.  So from there, you are saying that the next step would be a GPIB adapter.  Here be dragons, as I have never used anything with GPIB before.  I am happy to order one today if you (or someone) could point to exactly the one I should get (perhaps an e-bay link?) or are all these pretty much standard?

I also have a very nice GPSDO thanks to Nick Sayer's project:  https://hackaday.io/project/6872-gps-disciplined-xcxo

I assume that things will become clear the more I research GPIB and adapters?  I think that is the missing piece I was looking for in order to really use the Timelab software.

Thanks again for the help, all you time-nuts, as I seem to be ready to take the next step...

    -Randal R.
        (at CubeCentral)


-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Bob Stewart
Sent: Friday, 07 October, 2016 11:21
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Subject: Re: [time-nuts] Inexpensive Alternative to a 5120A

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
 -----------------------------------------------------------------
AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info

      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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