[time-nuts] Microsemi up for sale?

Magnus Danielson magnus at rubidium.dyndns.org
Sat Mar 3 14:32:20 EST 2018


On 03/03/2018 03:30 PM, Richard (Rick) Karlquist wrote:
> I asked the CBT manager at Microsemi about this
> rumor and he disavowed any knowledge of this.
> He told me they were making 8 a week (not clear
> if this is just 5071A's, or includes replacement
> CBT's).  I don't remember the production ever
> being anywhere near this level.  The reason
> for the relatively brisk sales is that the risk
> of GPS spoofing means that various military and
> 3 letter agencies need to own dedicated 5071's.
> With a large installed base of 5071's, there will
> be a guaranteed market for replacement tubes.
> The US government considers the 5071A to be of
> great strategic importance and would be certain
> to "encourage" its continued production in case
> of any business reorganization.
> When we designed the 5071A twenty five years ago,
> it seemed that there were two safe bets:
> 1.  Working Cs standards (outside the lab) would
> obsoleted by what HP called "smart clocks" running
> off of GPS.

We sure have seen more or less "smart" clocks being put into use an
decommissioned for hobbyists delight.

> 2.  Magnetic state selection, as used in the 5071A,
> would be replaced by optical pumping.  Len Cutler
> was heartbroken that HP/Agilent management wouldn't
> fund this effort.

Interestingly enough, Oscilloquartz claim to have one, showcasing it
etc. but it's been "coming real soon" for a bit of a time now. I do not
know how that progresses.

> It turns out that, even now in 2018, optical pumping
> is not ready for prime time in a working standard
> because the lasers drift over time.

Moving a technology from the lab environment into production is indeed a

> The 5071A's claim to fame is that you turn it on and it just
> works ... until it runs out of cesium.  That is
> another reason the 5071A isn't going away any time soon.

It belongs clearly to the moderns cesiums which just operates and trims
up itself well. In my basement I currently have two where one had a
workiing CBT and failing electronics while the other had failed CBT and
working electronics. So I got to long-time borrow them to swap tubes and
use them. :)


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