[time-nuts] HP 106B on Ebay

[timeok at timeok.it]

   Tom,

   Have you ever tested the HP106B for phase noise? And in particular between the HP106B and the BVA 8600 which is the best from this point of view?

   Luciano

   Luciano P. S. Paramithiotti
   timeok at timeok.it
   www.timeok.it

   Da "time-nuts" time-nuts-bounces at lists.febo.com
   A time-nuts at lists.febo.com
   Cc
   Data Sat, 21 Mar 2020 19:06:08 -0700
   Oggetto Re: [time-nuts] HP 106B on Ebay
   I second what Corby says. I have a number of hp 106, starting with one
   from eBay in 1999. Quite rare. When they work they are somewhere between
   very good and unbelievable. But most have issues. They are all very old
   by now and one trouble I've seen is that the double ovens don't work
   like they used to, which pretty much ruins their performance.

   So when you power it up it's a good idea to continuously log frequency
   (10 s gate is ok) for the first day or two and by looking at the
   wiggles, slopes, and slope changes, you can tell if the inner and outer
   oven are working right, or if one is dead, or if due to old age they are
   fighting each other.

   The daily ageing rate should slow down gradually. At some point (maybe
   months) environmental effects will exceed the ageing rate. These
   standards were meant to be powered up forever, in laboratory conditions.
   I had one that was far better than rubidium or cesium short-term, and
   almost rivaled rubidium long-term. It died of oven failure.

   Some photos, warm-up, and long-term plots:

   http://leapsecond.com/museum/hp106a/

   http://leapsecond.com/museum/hp106b/

   If you have questions feel free to ask us on- or off-list. And again, if
   at all possible collect data from the very first power-up.

   /tvb


   On 3/21/2020 4:47 PM, cdelect at juno.com wrote:
   > If whoever bought it needs advice I have repaired a couple of them.
   >
   > It does not have a dewar.
   >
   > Both the units I worked on had low to mid parts in 10 -13th from 1 to 100
   > Sec.
   >
   > They do take 3 to 4 hours to warm up so don't be impatient.
   >
   > Aging wont slow down for several weeks.
   >
   > Cheers,
   >
   > Corby
   >
   >
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