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Gentleman Seeks 1PPS — Parallax Forums

Gentleman Seeks 1PPS

tomcrawfordtomcrawford Posts: 1,126
edited 2014-06-01 16:07 in General Discussion
I just purchased a used hp5316B Universal Counter. It works fine and seems stable but I don't know what the absolute accuracy is. I would like to calibrate it by measuring a very good, preferable NIST-traceable timebase. If anyone in the Sacramento area has, say, a GPSDO 1PPS that I could bring my counter to, I would like to hear from you.
Tom Crawford

Comments

  • Duane C. JohnsonDuane C. Johnson Posts: 955
    edited 2014-03-13 19:26
    Hi Tom:

    The best, and probably cheapest, way to get 1ppS pulses is from a GPS.
    Not all supply this.
    You need one that has a dedicated 1ppS pin on the connecter.
    Some are better than others. However, all have a long term very high accuracy.
    Way better than the oscillator in the counter.

    BTW, I have one of those counters. I like it for the price. I paid about $75us as I recall.

    Duane J
  • ercoerco Posts: 20,256
    edited 2014-03-13 21:27
    A stream of 1 PPS pulses?

    Think about renaming this thread "Waiting for Baudot". :)
  • al1970al1970 Posts: 64
    edited 2014-03-13 22:04
    I guess nobody uses the beat to radio method anymore?

    Al
  • wasswass Posts: 151
    edited 2014-03-13 23:29
    The Fastrax UP501 is a cheap GPS module that has a 1 PPS output with extremely low jitter. So low that I can't measure it on my Racal Dana 1992 with the 04E option (high spec ovenized oscillator). http://www.ebay.com/itm/High-performance-and-Quality-UP501-GPS-Antenna-Module-For-Arduino-/170979281074
  • ErlendErlend Posts: 612
    edited 2014-03-14 04:11
    erco wrote: »
    A stream of 1 PPS pulses?

    Think about renaming this thread "Waiting for Baudot". :)
    Where is the 'Like' button!
  • Mark_TMark_T Posts: 1,981
    edited 2014-03-14 04:55
    Sounds like an excellent excuse to buy a 2nd-hand rubidium frequency standard to me!
  • tomcrawfordtomcrawford Posts: 1,126
    edited 2014-03-14 10:35
    wass wrote: »
    The Fastrax UP501 is a cheap GPS module that has a 1 PPS output with extremely low jitter. So low that I can't measure it on my Racal Dana 1992 with the 04E option (high spec ovenized oscillator). http://www.ebay.com/itm/High-performance-and-Quality-UP501-GPS-Antenna-Module-For-Arduino-/170979281074

    This looks like the best suggestion for a reasonable price. But a rubidium 10 MHz frequency standard sure would be cool!
  • Duane C. JohnsonDuane C. Johnson Posts: 955
    edited 2014-03-14 13:26
    Hi Mark & Tom;

    I did some work on the FE-5680A rubidium standard to change it into a general purpose frequency generator.
    See:
    FE-5680A

    Duane J
  • kwinnkwinn Posts: 8,697
    edited 2014-03-15 11:02
    erco wrote: »
    A stream of 1 PPS pulses?

    Think about renaming this thread "Waiting for Baudot". :)

    Good one, how about "Seeking Baudot" or "Searching for Baudot"
  • tomcrawfordtomcrawford Posts: 1,126
    edited 2014-03-25 08:54
    So I got a couple of Fastrax 501's.

    P1050111.jpg


    It looks to me like the oscillator in my counter is just about 1 part per million fast. The manual from hp tells you how to fiddle the osc but I think taking the cover off would be one of my dumber stunts. I'll just remember that 1.000001 is really 1.
    P1050111.jpg
    1024 x 768 - 101K
  • wasswass Posts: 151
    edited 2014-03-25 18:04
    tomcrawford wrote: »
    I'll just remember that 1.000001 is really 1.

    I used to keep a sticker telling me the same thing on a homemade counter years ago. I'm a little surprised that HP didn't make this counter easier to adjust.
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2014-03-25 21:00
    wass wrote: »
    The Fastrax UP501 is a cheap GPS module that has a 1 PPS output with extremely low jitter. So low that I can't measure it on my Racal Dana 1992 with the 04E option (high spec ovenized oscillator). http://www.ebay.com/itm/High-performance-and-Quality-UP501-GPS-Antenna-Module-For-Arduino-/170979281074

    This module is replaced by the U-Blox PAM-7Q. And, we have a board for it coming out next month, too! It's the best GPS we could find for performance, cost and availability. We've grown tired of having multiple GPS units and obsolete parts, so this time we've chosen a mainstream supplier for the long haul. All of our GPS shall be consolidated into a single product around the PAM-7Q. You won't have to make any decisions about what to buy because we'll only have the best module (and no choices!).

    Ken Gracey
  • jmgjmg Posts: 15,173
    edited 2014-03-25 21:29
    Ken Gracey wrote: »
    This module is replaced by the U-Blox PAM-7Q. And, we have a board for it coming out next month, too! It's the best GPS we could find for performance, cost and availability....

    No links yet ?
    How do your tests compare with the one mentioned above ?

    "The Fastrax UP501 is a cheap GPS module that has a 1 PPS output with extremely low jitter. "\

    I found new data (7 Mar 2014) on the PAM-7Q, but tagged 'Advance Information' ?
  • Duane C. JohnsonDuane C. Johnson Posts: 955
    edited 2014-03-25 21:30
    Hi tomcrawford;
    tomcrawford wrote: »
    So I got a couple of Fastrax 501's.

    P1050111.jpg


    It looks to me like the oscillator in my counter is just about 1 part per million fast. The manual from hp tells you how to fiddle the osc but I think taking the cover off would be one of my dumber stunts. I'll just remember that 1.000001 is really 1.
    Adjustment is quite easy from the back panel. You don't need to open it up.
    See HP 5316B Operation on page "3-18" and figure "3-11".

    Duane J
  • wasswass Posts: 151
    edited 2014-03-26 02:51
    This module is replaced by the U-Blox PAM-7Q. And, we have a board for it coming out next month, too!
    Ken Gracey

    The specs on this look great, especially the lower voltage/current requirements and the programmable pulse output (.25Hz to 1KHz)
  • Tracy AllenTracy Allen Posts: 6,664
    edited 2014-03-27 09:40
    Tom, I see that the HP5316B has a couple of optional frequency references that can be added in place of the stock stable xtal oscillator, option 1 for a TCXO and option 4 for an ovenized xtal. Increasing warmup times to best stability. I'm thinking about getting one of those off ebay, or an HP5315. What do you recommend about the options?
  • tomcrawfordtomcrawford Posts: 1,126
    edited 2014-03-27 09:56
    Tracy Allen wrote: »
    Tom, I see that the HP5316B has a couple of optional frequency references that can be added in place of the stock stable xtal oscillator, option 1 for a TCXO and option 4 for an ovenized xtal. Increasing warmup times to best stability. I'm thinking about getting one of those off ebay, or an HP5315. What do you recommend about the options?

    Gee, I guess it depends of what kind of stability you need. If I had known about the options, I would have gotten option 4, if I had found one. But I think I would have pretty much had to turn it on and leave it on to take advantage. The one I got doesn't have *any* option (not even TCXO) and the short term stability is good enough for me. And I can calibrate it with my fancy Fastrax whenever I feel the need. So you pays yr' money and you takes yr' choice.
  • Tracy AllenTracy Allen Posts: 6,664
    edited 2014-03-27 21:19
    Tom, thanks for the tips and for bringing this up. I was in the market. I ended up with this one, which has the option 1 TCXO and also the option 3 channel C GHz prescaler. Ebay is always a risk, but I try to read between the lines. I've purchased several HP/Agilent test instruments and power supplies off ebay and have not been disappointed.

    I'll now await the arrival of the Parallax U-Blox PAM-7Q module, for 1pps and for knowing where the heck I am.
  • wasswass Posts: 151
    edited 2014-05-31 08:33
    Ken Gracey wrote: »
    This module is replaced by the U-Blox PAM-7Q. And, we have a board for it coming out next month, too! It's the best GPS we could find for performance, cost and availability. We've grown tired of having multiple GPS units and obsolete parts, so this time we've chosen a mainstream supplier for the long haul. All of our GPS shall be consolidated into a single product around the PAM-7Q. You won't have to make any decisions about what to buy because we'll only have the best module (and no choices!).

    Ken Gracey

    2 months later ..... I don't see these yet in the Parallax store, any news on when they'll be available?

    Thanks!
    -Katie
  • PublisonPublison Posts: 12,366
    edited 2014-05-31 09:51
    Ken is on currently. Maybe he has a timeline.

    I am also interested.
  • Too_Many_ToolsToo_Many_Tools Posts: 765
    edited 2014-06-01 12:33
    Publison wrote: »
    Ken is on currently. Maybe he has a timeline.

    I am also interested.

    As am I.

    And who is the supplier of the GPS chip set?
  • PublisonPublison Posts: 12,366
    edited 2014-06-01 16:07
    Too_Many_Tools wrote: »
    As am I.

    And who is the supplier of the GPS chip set?

    As per Ken's post#13:

    U-Blox PAM-7Q
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