[time-nuts] A fan for the Z3801A

[Murray Greenman]

Alberto,

I'm not much in favour of the idea of adding a fan (to any GPSDO, not
just the Z3801A). While I've not tried it, there would be a risk of
upsetting the stability of the unit, especially if the fan speed varied
or the air flow changed for some other reason. If you could be sure that
the airflow was steady and was not directed at the OCXO, it might be OK,
but test it out.

In my experience with the Z3815A I noticed a marked change in frequency
(it returned and settled after a while) when I turned the unit gently
upside down, i.e. reversed the direction of convection.

It would be preferable, in my opinion, to simply improve the convection
paths in your present setup.

As an aside, it is interesting to note the steady-state power
consumption of the various units. The Z3801A is spec'd at 25W, the
Z3815A (with hockey-puck oscillator) 35W, and at the other extreme, the
Trimble NTGS50AA only 5W!

73,
Murray ZL1BPU