[time-nuts] Portable standard - Rb query

Murray Greenman Murray.Greenman at rakon.com
Wed Apr 6 18:34:19 UTC 2011


Joe,
I have several of the FEI units. You pay more for these, because
(assuming you get the right one) they have a DDS synthesizer included,
which (with suitable modification) allows them to operate from about
1kHz to 15MHz in 10mHz steps. Some models require +15V and +5V, others
just +15V. My preferred unit is the FE-5680A. I have mine mounted on a
large aluminium plate and powered by a switch-mode computer supply. I
have set the default frequency to 10MHz.

The LPRO type are fine if you want a simple fixed 10MHz reference, and
are in general cheaper and use less power.

As for lifetime, they seem to go forever. That said, there's no need to
power them continuously since (in my experience) they are close to their
final frequency 5 minutes from a cold start. Power consumption is higher
than an OCXO, but they really do make a great portable standard. That's
what I'd use (in fact, that's what I do use). 

Murray




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