[time-nuts] BVA 8600 Power

[ew]

Going through this process on my 8607 and looking back on 50 years of frequency work let me first say: any one doing serious work with OCXO's, Rb's and GPSDO's should have power back up. In the 70's in Dallas I used round 20 A 2V Gould cells for the in ground Sulzer, in the 80's for my first FRK Gould 4A Gould Ni Cads. In Miami added large flooded Trojans. Always 12V. In Dallas a New Years eve ice storm, in Miami Hurricanes but the biggest problems where Seniors driving in to power poles and transformers. Here in Palm City over 5 years max outages 3 hours mostly lightning related. Last week Juerg had his first major 3 hour power outage, first in 10 years. To us there are two reasons for backup. Be able to move unit without power interruption. Second power outage. Attached Juerg's answer to power backup for his HP 5065A. It also uses a Mean/Well RSD-60. Now to OSA 8600. Spec says  24 V +- 10%.  We do not know what the inside looks like but tests show that there is a regulator on the input. Current does not change as you step from 24 V down to 20 in 1 V steps. But below 21 V we see changes. So if you have to start out with 24 V it is safe to use a low noise linear regulator like the LT 3081 with 3 V drop. Caution all DC DC switchers need a PY filter on the input!! more important than output filtering. The Mean/Well SD DC DC series is very flexible have adjustable output in case of the 24 V unit  21 to 29 V.  Have to many different SD units if any one in the market contact me off list. In my case on the 8607 I will use a RSD-30 with 24 V output followed by a low noise regulator output at 21V. Performing tests right now use a 9 Lb 12 V 22A AGM for mass, or Li Ion. Input 100 to 240 AC and 9 to 15 V DC. 8607 will be in a sealed metal enclosure to keep at constant pressure. Box  will arrive today and tests will start. Bert Kehren    In a message dated 9/25/2020 3:38:45 AM Eastern Standard Time, notfaded1 at gmail.com writes: 
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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