[time-nuts] Connections for FE-5680A rubidium sources
brayniac at gmail.com
Tue Dec 16 16:36:50 EST 2014
I just power mine off an old 19vdc laptop supply dropped with a linear
regulator (and filtered) to provide ~17vdc No 5vdc supply required for
mine. I recall reading that some have an internal 5v regulator. I believe
the way to check is if the lock pin signals and PPS is present without
external 5vdc supply. Mine does. Your experience might vary - but that was
my experience with my copy.
I also didn't have serial connected on mine. Had to mod it to bring out
serial. Anybody else face that?
On Tuesday, December 16, 2014, Ryan Stasel <rstasel at uoregon.edu> wrote:
> It's interesting, but I've actually found the FE-5680 I have will power
> up, and lock, from just 12v. Sure, takes a bit longer, but it eliminates
> the need for the 7812 in the box, etc. I know the 5680 FAQ on ko4bb (
> states they'll run as low as 9.96v, but I've always been curious if that
> was AFTER the 15v lock, or from cold.
> Anyway, YMMV on any particular unit, but it would be interesting to hear
> if anyone else is just powering them from a standard (linear) 12v wall
> wart, or are you all just using 15v?
> -Ryan Stasel
> > Hello,
> > I've mounted both my LPRO-101 and FE-5680 in Hammond 1590-type cast
> aluminum boxes, bolting the rubidium unit to the lid of said box, and found
> the heat sinking of the entire arrangement to be entirely adequate. In
> each case there is a (well filtered!) switching regulator present that
> contributes little to the overall thermal load as well as allowing them to
> run directly from a standard "12 volt" equipment bus.
> > If you run the units at their minimum allowed voltage (19 volts for the
> LPRO-101, 15 volts for the FE-5680, IIRC) they will dissipate much less
> power as the regulators contained therein are linear type. It struck me
> that at the lower limit voltages that they take slightly longer to warm up
> and come online, but still somewhere around the 3 minute mark for a
> "Physics Lock."
> > Details may be found at:
> > http://www.ka7oei.com/10meg_rubidium1.html - For the LPRO
> > http://www.ka7oei.com/10_MHz_Rubidium_FE-5680A.html - For the '5680,
> of course!
> > 73,
> > Clint
> > KA7OEI
> >>> Hi
> >>> One fairly important issue - the unit needs to be on a heat sink. If
> >> run it without cooling of some sort, it will not run for very many
> >>> Bob
> >> I do realize that, but how big? Normally "the bigger the better" is
> >> not an unreasonable rule on heatsinks, but I have heard that cooling
> >> these too much is bad. I have here a heatsink about 600 x 300 x 150
> >> mm, although I think that is a bit OTT !!
> >> Dave
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