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Anyone played with rubidium frequency standards?

Discussion in 'General Electronics Discussion' started by (*steve*), Apr 3, 2012.

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  1. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    I've just wired up mine and gotten a nice looking 10MHz signal out of it. Has anyone played with these?

    It takes about 2:30 to stabilise from "warm" i.e. off for about half an hour. Does that seem reasonable? I'll measure it again from cold tomorrow.

    I mounted it on a huge heatsink (something large enough to mount it on with its 15 mounting holes!). The only thing is that it seems that the top of the unit gets hotter than the bottom. Is there any point in placing a heatsink on the top as well? Or will I just be cooling the bits it wants to keep warm?

    I don't suppose there's anyone here that has a really good frequency meter they can send over to me for a while? As long as it's good to about 1 part in 10^7 or better I can confirm that the frequency is close. :)
     
  2. duke37

    duke37

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    Jan 9, 2011
    If the stadard is temperature stabilised, then surely it should be at an even temperature.

    Do you have a 10MHz radio frequency standard available WWV or WWVH?
     
  3. KJ6EAD

    KJ6EAD

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    Dave Jones got into one a bit on his EEVblog (episodes #235-6).
     
  4. shrtrnd

    shrtrnd

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    Jan 15, 2010
    We don't consider our freq standards reliable until they've been running for4 24 hours, but we
    never turn ours off. (We use rubidium and cesium)
    You'd have to have a electronics standards lab calibrate the unit, to be absolutely
    sure of accuracy.
    You need the oven (heater), to maintain stability. Your freq will change with temperature
    (and barometric pressure, and humidity), but I doubt enough to make a difference in
    anything you do.
    Our standards are tied to NIST, continuously.
    If you weren't about 8,000 miles away, I wouldda fixed you up.
     
  5. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Yeah, I'm not overly concerned about the ultimate stability, but I'd like to know it's reasonably accurate. I'd like to see it being 10,000,000 Hz, not 10,000,200 Hz (some people have reported these being that far out).

    Where it might be in 9,999,999.99 to 10,000,000.01 Hz is totally irrelevant to me.

    shrtrnd, maybe I'll drop in next time I'm in the neighbourhood!
     
  6. davenn

    davenn Moderator

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    Sep 5, 2009
    hey Steve,

    There's a whole bunch of us anateur radio ops that have bought rhubidiums off ebay over the last couple of years. Mine gets used as a 10mHz ref for my synth's operating in my 10 GHz and 24GHz transverters.
    They do get quite warm huh !! :)
    Cant remember the model # of mine offhand, I'm not at home. upwards of 30 mins and its well stable enough for our tranceiver operations. An hour onwards and it is pretty stable.

    My mate and I were playing with my rhubidium and his GPS locked 10MHz osc, feeding both signals simultaneously into an oscilloscope. was very interesting.
    this one.... http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm
    The rhubidium blew the GPS source out of the water for stability.
    It was interesting watching the GPS pulling the 10MHz osc into line every few seconds

    Dave
     
  7. shrtrnd

    shrtrnd

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    Jan 15, 2010
    Your standard should be a lot more than reasonably accurate, for most uses anyway.
    Obviously it's not the rubidium that's at issue, it's all those pesky OTHER electronic
    components that measure the decay that are the issue, in the reference standard circuitry.
    It sure is nice to see the display read 10,000,000.000000HZ though, isn't it.
     
    Last edited: Apr 4, 2012
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