[time-nuts] Re: Coupling between oscillators -- an example

[Richard (Rick) Karlquist]

On 3/25/2022 12:41 PM, John Ackermann N8UR wrote:
> 
> 
> PS -- an interesting feature of these oscillators is that they are an 
> "S12" variant that has a little accelerometer bolted on and hooked to 
> the EFC circuit to compensate for G forces.  These were ship-board Cs 
> units, so I wonder if the accelerometers were intended to compensate for 
> ordinary ship vibrations, or maybe the firing of the big guns. :-)
> 

During the initial debug of the early 5071 prototypes (circa 1990)
it somehow came to light that 5061's on ships had a phenomenon where
the frequency would be slightly, but noticeably affected by the
slow rolling motion of the ship.  Len Cutler and our CBT genius
figured out that the problem was in the cesium beam tube.  Therefore,
the 5071 would also exhibit this problem.  The CBT was modified before
the 5071 release and the problem was eliminated.  IIRC, the problem
had to do with the Cs atoms being ballistic objects that didn't hit
the bulls eye if the CBT was moving.  I seem to recall that the
problem was a result of some other problem they tried to fix, but
the fix was too clever by half as they say.

Possibly, this is related to the units you have.

Regarding big guns:  one of the specs the 5071 (and 5061) had to meet
was the "hammer blow test" which simulates the firing of big guns,
using a 400 pound hammer that strikes a frame in which the DUT
is mounted.  It's OK if the DUT suffers structural damage ...
as long as the DUT keeps working.  I think it is allowed to
momentarily go off frequency during the test.

Rick N6RK