Corby, Thanks for your informative posting. I concur. Let me add a visual that echoes your comments. It's the same plot that I attached in the note about Ralph's lab. For those of you who can't view email attachments see [1].
The plot is ADEV of 4 typical lab frequency sources: - A 5071A in Ralph's lab, on loan from NIST. - A 5065A Ralph owns, which has some 120 Hz noise, but excellent stability beyond tau 1 s. - The 10 MHz ref out of a Agilent/Keysight 53230A counter (XO or TCXO, not sure). - The 10 MHz ref out of a SRS SG348 signal generator (OCXO option). Note the difference between the 5065A and the 5071A in the plot. You can see why for many experiments a 5065A is preferred. I mean, over a wide range of tau it's 4x better. OTOH, if you want to make short-term measurements against a cesium standard, by all means turn off the Cs beam and let it free-run. Both the 5061A and 5071A make this easy. /tvb [1] http://leapsecond.com/tmp/2018b-Ralph-4-adev.png ----- Original Message ----- From: <cdel...@juno.com> To: <time-nuts@febo.com> Sent: Saturday, February 24, 2018 2:14 PM Subject: [time-nuts] Selling Time and Frequency Equipment Or "just saying" > First, full disclosure, I have no vested or financial interest in the > 5065A he is selling. > > Now the 2816A prefix is the last series built so the most modern. > The last one I remember on eBay went for OVER $4000.00 > > Comparing a 5065A to a Cesium (except maybe a working 5071A for the same > price)\is worse than Apples and Oranges. > > Ask Bert who got rid of his 5065A years ago because he had a Cesium, he > regrets that now and just got a new one! > > A 5065A buyer is looking for the best short term stability he can find > (nominal 1.5X10-13th at 100 Sec) > Keeping on frequency is easy via GPS comparisons. > > A Cesium buyer want NIST traceable accuracy "out of the box" and never > (practically) having to adjust the frequency. The Cesium will be worse > when compared to the 5065A at shorter Tau even if it has a high > performance tube. > > Another thing to consider when buying a Cesium is what is the condition > of the tube. The tube will die, just don't know when. (probably at the > most inconvenient time!), and lets not ask what a replacement tube costs! > > There is no perceptible wear mechanisms in play for the 5065A (I have > seen exactly one failed lamp in many years of working on them) Many of > the first 1968 series built will still perform to specs today. > > So, > > Just saying! > > Cheers, > > Corby
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