[time-nuts] Power supply for time source concerns

[Dana Whitlow]

I, too, am baffled by why some Rb standards use separate pins for oven power
and electronics package power, especially since they don't seem to use
separate
return pins as well.

At Arecibo we had a utility PRS-10 mounted in a box with fan along with 1
each
switching supply (for the oven) and linear supply for the electronics.  It
seemed
not to have any problems.

I also would like to know whether or not there is risk of damaging a PRS-10
if
one or the other of separate supplies fails and the unit spends some time in
that situation (like hours or days).  I particularly worry about the case
of the oven
supply staying on while the electronics supply had gone off- could the oven
control then put full power to the oven indefinitely, risking destruction
of the
physics package?

2nd question: can anybody tell me what level of switching-frequency
sidebands on
the 10 MHz output of an Rb is *generally* considered "bad" versus "good"?

Dana


On Tue, Dec 24, 2019 at 6:05 AM Poul-Henning Kamp <phk at phk.freebsd.dk>
wrote:

> --------
>
> >That again depends on topology and control type.  The canned converters
> >are almost always optimized to have the lowest number of switches and
> >work with cheap magnetics (single coil) without easily entering
> >problematic operation modes, noise is only a secondary concern.
>
> That depends a LOT on which canned converter you decide to buy,
> if you only go after price, or W/mm³ capacity, then certainly yes.
>
> But for a one-off application like this, any money saved on a
> cheap model is easily lost many times over in the trouble it will
> cause.
>
> But returning to the original post:  Has anybody ever characterized
> how much difference it makes to use two different PSU's for heater
> vs. electronics sides of telecom Rb's ?
>
> I'm sure there is a reason why they make it two different pins ?
>
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
>
> _______________________________________________
> 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.
>