[time-nuts] Vibrations

[Magnus Danielson]

Raj wrote:
> While comparing a Rb FE5680 frequency reference with another RB or GPSDO I find that tapping a Rb unit causes a sudden shift in the scope display meaning the frequency has slightly shifted momentarily and locks back steadily with a phase shift. This does not happen in another Rb FE5680.
> 
> Would something be loose I wonder ? Any experiences?

Well, last weekend I just *happend* too look into a pair of FE5680 at a 
friends place. The crystal oscillator did not impress me much at all. 
The standard crystal was mounted onto the middle board in a stack of 
three on the cold compartment. Mounting did not provide any vibration 
damping from the case into the crystal, so you will have microphonics 
straight into the crystal.

So, I think that your experience should be expected or at least reasonable.

Cheers,
Magnus