[time-nuts] OCXO sensitive to gravitational effects

[Magnus Danielson]

Lux, Jim (337C) wrote:
> Or, as it was explained to me, the magnetic field causes the holder to move, which puts a mechanical stress on the crystal, which changes the frequency.
>   
Just how much depends on the details not only on the holder parts but 
also how the crystal is mounted. The extreme case here is the BVA 
crystals, where the oscillating crystal piece is not held by traditional 
holders, but with an extended part of the same crystal, which should 
almost completely remove the magnetic coupling (to the crystal).
SC cut crystals is expected to behave much better than AT cut in this 
respect, as they should compensate for mounting stresses to a much 
better degree.
> And an AC field can induce a voltage in a loop (i.e. The wires going to the crystal), which then moves the crystal, etc.
>   
Indeed.

SC-cut crystals is however sensitive to E-fields and a static DC field 
will shift the frequency. This is also part of the frequency jump 
mechanism, as the cleanness makes point charges on the crystal can stay 
for very long time, but when a single ion atom leaves, the E-field 
changes and the jump is a fact.

I beleive other cuts also have E-field sensitivity, but I can't recall 
seeing any specifics on it, but I haven't really looked either.
> Limitless things to worry about in extreme time-nuttery...
>   
Yes, it is an effective hobby in that you can't stop... :)

Cheers,
Magnus