[time-nuts] Oscilloquartz BVA has been sold. Thank you all who expressed an interest.

[Tim Shoppa]

Bill, most modern double-oven OCXO's (including I think the BVA under
discussion) are under 5W average consumption after warmed up.

Most UPS's are rated for near-peak-power output (most of a kW or more) for
5 or 10 minutes to give time to shut computers down gracefully and are not
sized well for keeping a single 5W device powered up for hours (days?
depends on your requirement) although you can use them that way with a
substantial loss of efficiency.

Figure out your needed hang-time, and size 24V gel-cell or AGM battery to
keep the OCXO's ovens warm and oscillator humming. Diode-or'ing works well
and if you need to account for a 24V gel cell really being 28V under float
charge, use multiple series diodes in that leg to get voltage drop to it
being under 24V. The spec about frequency shifting under Voltage change is
not really relevant if you aren't using the output during the power outage.
You just want to keep the oscillator ticking and ovens warm to prevent
having to re-age after an outage.

Tim N3QE

On Fri, Sep 25, 2020 at 3:38 AM Bill Notfaded <notfaded1 at gmail.com> wrote:

> I plan to keep BVA powered.  My question was how do you accomplish this and
> what do you do it with?  I've been using PS like for example Fluke
> PM2811, Tekpower TP3005T, Dr. Meter HY3005F-3 (these are similar), Sorensen
> and some older HP.  I've had good luck them all so far.  I'm curious if
> someone's found some better way that's smaller and newer and still good?
> It looks like a big UPS is in my future.  Luckily I rarely have power
> outages here even in the desert of the southwest in AZ where the temp and
> even humidity is mostly stable inside in the AC in summer and even heat in
> the winter.  It's dry in both cases inside in my lab.
>
> Do you monitor the thermistor along with the frequency and external
> temperature/humidty?  I've been using this for external:
>
>
> http://www.dogratian.com/products/index.php/menu-sensors/menu-usb-pa-type-a-bmp085
>
> It seems to work pretty well to monitor temp and humidity with USB for the
> room plugged into my computer.
>
> What I'm starting to think about is how do this on much larger scale at the
> same time?  I have a few counters 53131, 53132, CNT-90, and an SRS SR620
> but how do you do long term measurements over long extended periods on
> multiple powered up oscillators?  Is there a mass way to do this?  I know
> the computer could handle this with GPIB but is there another better way to
> say monitor all these variables on say 5 to 10 DUT constantly easier?  I
> have an HP3458A but I wouldn't want to keep it tied up too long.  The
> counters I run a lot so that's not a problem really.  What do you
> orchestrate the whole thing with?  I have labview NXG but I'm not sure some
> hardware DAQ or something with some scripts might not be better for
> multiple DUT than messing with labview running all the time.
>
> How do you do it?  How do you get stats on multiple oscillators for years?
> I suppose some oscillators deserve their own dedicated counter 24*7 and
> maybe even a raspberry pi to sample the GPIB.  I do have a few USB to GPIB
> interfaces and Pi's are pretty cheap but I've only got a 2 and a 3 right
> now.  But then is there a timelab for Linux?
>
> I suppose the first main key is to just keep all the OCXO and GPSDO's
> powered all the time first on a UPS?
>
> Thanks,
>
> Bill
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