[time-nuts] fleabay cesium

WB6BNQ wb6bnq at cox.net
Sat May 9 06:48:35 UTC 2009


   Well Dick,

   Assuming it is setup and properly adjusted, it is absolute as a
   frequency reference by "definition."  It does have a given resolution
   as stated in the manufacturer's manual for the instrument.  This
   resolution [or noise floor as I see it] is due to a number of factors,
   not least of which is the condition of the physics package (the actual
   Cesium tube).  They do ware out !

   Time is another matter all together.  the 5061A has a rated accuracy of
   1 x 10^-11 and reproducibility of 5 x 10^-12.  Thus it can be
   considered that the unit drifts by 1 part in 10^-11 and that means the
   time is drifting by that much.  As time is relative you always have to
   compare against another clock to determine where you are relative to
   the other.

   You could own the very latest, top of the line Cesium (absolute to
   parts in 10^-13) and still have the time problem.  So it becomes a
   matter of what your needs are and your applications for which it is
   used as a reference.

   The manual for the hp 5061A is available via the Internet and if you
   can't find it let me know and I can send a copy.  It would do you well
   to read it and gain an understanding of its fundamentals.  There are
   other publications that would be worth studying; if you want or need
   those let me know as well.

   73....Bill....WB6BNQ

   "Richard W. Solomon" wrote:

     OK, dumb question time.

     I have a few GPSDO's (Trimble T-Bolt, Z3801A, TrueTime & HB units).
     How much better can the Cesium be than any of those ??

     73, Dick, W1KSZ

     -----Original Message-----
     >From: ewkehren at aol.com
     >Sent: May 8, 2009 12:53 PM
     >To: time-nuts at febo.com
     >Subject: Re: [time-nuts] fleabay cesium
     >
     >The cesium is from the same source as the two HP 5062. A friend of
     mine is selling them for me. I am in the process of cleaning house
     and that is also where the FTS1200 came from. More things are to
     come. I think this one is a later model because it has the newer
     power supply board and the DC cesium oven controller. I think it is
     the one unit. It should say in the description. I know I tested it,
     also measured beam current with the LF test. It des not have the two
     lights but during test they where installed and the pictures are of
     the actual unit. If you want to know any thing else please let me
     know.? Bert Kehren Miami
     >
     >
     >-----Original Message-----
     >From: Brian Kirby <kilodelta4foxmike at gmail.com>
     >To: precise time and frequency measurement <time-nuts at febo.com>
     >Sent: Fri, 8 May 2009 12:06 am
     >Subject: [time-nuts] fleabay cesium
     >
     >
     >seems to be a decent price cesium for sale ($600 starting HP5061A)?
     >?
     >[1]http://cgi.ebay.com/HP-5061A-Cesium-Beam-Frequency-Standard-WORK
     ING_W0QQitemZ250415440530QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=
     item3a4dec6292&_trksid=p3286.c0.m14&_trkparms=72%3A1205|66%3A4|65%3A
     12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A200?
     >?
     >nobody has bid and 21 hours left...?
     >?
     >just a heads up - I know nothing about the unit or the dealer...?
     >?
     >Brian KD4FM?
     >?
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References

   1. http://cgi.ebay.com/HP-5061A-Cesium-Beam-Frequency-Standard-WORKING_W0QQitemZ250415440530QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3a4dec6292&_trksid=p3286.c0.m14&_trkparms=72%3A1205|66%3A4|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A200
   2. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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