James Robbins wrote:

To the time nut who ended up with this BVA -- do not worry if it looks
like it is broken when you power it up. These oscillators take their
time to warm up. Here is a test I did last year on a similar BVA oscillator:

"Oscilloquartz 8600-series OCXO warm-up"
http://leapsecond.com/pages/osa-warm/

/tvb

Thanks Tom-

I really appreciate your comment.  I've studied your website closely on
this topic.  I'm really in awe of the 860x models some of you have access
to 8607, 8608 models some with options!  I'd probably be considered a newer
school timenut/voltnut but... I even collect Nixie tube frequency
counters... Separate topic but wow I just love cold cathode display
technology and mixed with frequency... well dekatron counters too.  Props
to Jim for making BVA available here before putting on the auction site!  I
have mad respect for that.  I've found some of the best people here.

Best Regards,

Bill

On Wed, Sep 23, 2020, 4:29 PM Tom Van Baak tvb@leapsecond.com wrote:

Hi Tom,

I second this, these oscillators you want to power up and just leave for
them to settle and then keep powered.

Next time I power down mine is to integrate a new supply and back-up
batteries, which can be a recommended little exercise. Currently only
the H-maser is on battery backup.

Cheers,
Magnus

On 2020-09-24 01:25, Tom Van Baak wrote:

Hi All.  I have a related question..

From a maximizing the life span of the BVA perspective if one only wants to use it once a year or so and can wait for a month or so for it to stabilize, does it make more sense to mostly leave it powered down or is leaving it running all the time a better plan ?  I realize this type of question may not have an definitive answer but I am curious about the views of others.

I have a couple of other OCXO's that I leave running all the time and have never quite gotten around to putting together a guaranteed to never go down DC supply for my BVA.  My read on the voltage specs for my BVA discouraged me from simply powering it from my 24 volt DC battery bank that is float charged at a somewhat higher voltage when AC power is available.

Given the typical price of a BVA, I don't have a spare BVA in my time lab and would like to maximize its life.  Over the years several other pieces of gear have failed but I have spares for them (:

Thanks in advance for any comments.

Mark Spencer
mark@alignedsolutions.com
604 762 4099

May I recommend PowerPole connectors and frequent use of diode-OR. For
details see:

http://leapsecond.com/pages/powerpole/diode-or.htm

I got the inspiration when my Dad was in the hospital and I saw how they
did IV tubes with multiple injection points. It seemed so simple,
clever, reliable. Details [1] and graphic photo [2].

So now I use diode-OR "Y" connectors on all my long-term standards. It
allows me to replace either power supply live without interruption at
any time. Come to think of it, they call it an IV in the hospital. And
here in my lab the I is about 0.18 and V is 24 so my IV is 4 watts. ;-)

/tvb

[1] https://en.wikipedia.org/wiki/Intravenous_therapy
[2] https://en.wikipedia.org/wiki/File:ICU_IV_1.jpg

On 9/24/2020 12:38 PM, Magnus Danielson wrote:

Seconded!  I don't have that set up on all my oscillators, but plan to
get there.  I do have things set up so I can remove the 24V battery
bank for maintenance and run directly on the AC power.

BTW, I've standardized on using orange-black PowerPoles for 24V
(red-black for 12/13.8V, green-black for 5V, etc.).  West Mountain Radio
has 24V distribution panels with over/under voltage monitoring and
orange-black connectors.

And, if you use PowerPoles, please spring the $30 and get a crimping
tool.  It makes life so much easier, and connections so much more reliable.

John

On 9/24/20 5:47 PM, Tom Van Baak wrote:

Hi

Maximize life = put it on the shelf and never power it up. It (may) last for a century that way.
How you will know it’s still doing fine is very unclear.

Maximize utility = power it up and keep it on power all the time. If you can plan well, power it
up 9 months before you need to use it.

There is a lot of data suggesting that > 90 days of stabilization is a good idea on OCXO’s.
That’s based on fairly basic parts. On something fancy, it’s a good bet that even longer is better.

===

Does it need to be on power at 24V +/- 0.00000001 V for 9 months ahead of time? Is a 1 hour
power outage 3 months back a really big deal? Both are in the “that depends” category.
Good bet is “don’t worry about it.”

One practical approach is to mount a regulator external to (and thermally isolated from) the
OCXO. Then apply whatever supply you happen to have. Net result is that the device does
not see any crazy voltage spikes. A diode “voting” setup could also be integrated into the
regulator board.

Bob

Thanks Bob that is helpful.

The external regulator approach you mention was the direction I was headed in for powering the BVA, but I realized that I would need more than 24 volts into a simple linear regulator to get a stable 24 volt output which complicated using my existing 24 volt battery system.

Maybe I am over thinking this.

For now I run the BVA as needed
from a lab supply that is powered by a UPS.  A better backup scheme is something  else to look at down the road as I get back into the time nuts hobby.

I really appreciate my FTS1050 and HP105B with their separate AC and DC power connections in this regard.

Mark Spencer
mark@alignedsolutions.com
604 762 4099

What power supply do you recommend for the BVA. I'm kinda partial to high
quality linear power supplies.  I'm not so concerned about the size or the
efficiency.  I'm more concerned with clean power that's stable like the
oscillators I'm trying to power.  I'd be interested in what others think?
I know you can often get by with a switching power supply for some things
and many OCXO and GPSDO's have they're own power filtering and smoothing to
some degree.

Bill

On Thu, Sep 24, 2020, 12:46 PM Magnus Danielson magnus@rubidium.se wrote: