[time-nuts] Re: What's the best HP OCXO for frequency counter reference?

[Bob kb8tq]

Hi


> On Jun 28, 2022, at 12:15 PM, Hal Murray via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> 
> Adrian Godwin said:
>> If you use the ovened oscillator for temporary use away from the home GPSDO,
>> how good will the oscillator be with those interruptions to power /
>> temperature, and will it stabilise during the period you're using it there ? 
> 
> You can solve that with a UPS and/or a gizmo that plugs into a car accessory 
> socket.

You still power it down doing that. Power cycle generally isn’t a good idea if you 
are after good stability. 

> 
> How much does the mechanical jostling as gear gets moved from bench to car to 
> table effect the frequency?

If you flip it end for end you might be measuring the “2g tip” acceleration sensitivity :).
That could be up in the 1 to 2 ppb range. Shock and vibe is very much a “that depends”
sort of thing. You could (but probably won’t) see a couple of ppb.

The biggest issue is going to be the changing temperature environment. Thermal shock
is going to create a bigger change than simple temperature change. Going from inside 
to outside to car to outside to inside …. each one is a relatively fast change. You might
have a device that held a ppb in a normal temp test and it changes 10X that (or more) 
when hit with a relatively modest “fast change”. 

Just what’s fast and how much of a change you get is very much a “that depends” sort
of thing. Leave the cover off your OCXO mechanical trimmer and you could find that it
is very sensitive to a gentle gust of wind from the wrong direction ….

Bob

> 
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