[time-nuts] Connections for FE-5680A rubidium sources

Clint Turner turner at ussc.com
Tue Dec 16 12:54:21 EST 2014


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 



> On 16  December 2014 at 12:16, Bob Camp<kb8tq at n1k.org>  wrote:
>>   Hi
>> One fairly important issue - the unit needs to be on a heat  sink. If you
> run it without cooling of some sort, it will not run for very  many years.
>> 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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