[time-nuts] Power supply for OCXO using "USB power blocks"

[Taka Kamiya]

Nortel GPTM operates on 24 or 48V DC.  Internally, there is a step down dc/dc converter and 3 terminal regulators.  It creates whatever it needs internally.  So it can be done.  It does have quite a bit of filtering though.  I have run Oven oscillators with a regular cheap switcher.  Spec says ripple is 150mV p-p.  I really didn't have problems using it as a reference clock.  If I were to multiply it to GHz range, it would likely not work.

According to spec for Wenzel Streamline, it says 15V or 12V 2.2 watts.  Warm up is 5 watts at 5 minutes.
Seem like one can simply get 12V battery of sufficient capacity and run with that.  If I were to consider a portable operation, I would rather have gell cell batteries. It's a simple and proven technology with no catastrophic failures. I would also have it large enough so it can be started ahead of time and keep it running.

--------------------------------------- 
(Mr.) Taka Kamiya
I'm stuck in a wormhole....  Hello, worms! 

    On Saturday, March 9, 2019, 11:03:45 PM EST, Gerhard Hoffmann <dk4xp at arcor.de> wrote:  
 
 
Am 10.03.19 um 01:38 schrieb jimlux:
> Has anyone tried a +5V to +15V DC/DC to run an OCXO, getting the 5V 
> from one of those rechargeable USB power bricks.  I was thinking about 
> portable operation.
>
> In my case, the OCXO is something like a Wenzel streamline. I would 
> think that the DC/DC probably has some noise, but maybe DC/DC to a 
> higher voltage, then a good linear regulator to clean it up (or would 
> the radiated noise just leak around).
>
> How quiet is the output from those USB battery things..I've used one 
> to run a RTL-SDR, but that's hardly a ultimate low noise receiver.
>
That's impossible to predict. These boxes normally contain one Lithium 
cell and a DC/DC converter to 5V.

Its output noise depends on the skill of the designer and the mood of 
the bean counter. It is probably

not a high priority. Also, there my be "effects" from the interaction of 
their switcher and your's.

And the efficiencies multiply.

BUT:

3 of these Li cells deliver 12V in ultimate quality:

< 
https://www.flickr.com/photos/137684711@N07/39972841815/in/album-72157662535945536/ 
 >

The squares on the paper are 5mm.


Noise density is better than 1nV / rtHz above 100 Hz. You definitely 
need a fuse.  Ishort is >> 30A.

This Panasonic type is OK. There are lots of others on the market that 
claim twice the power capacity

but it's a blatant lie.


regards, Gerhard

(who thinks about using a dozen of these for portable EME tests on 432 :-) )


_______________________________________________
time-nuts mailing list -- time-nuts at lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.