[time-nuts] Rubidium as radio reference

[Chris Albertson]

On Tue, Oct 30, 2012 at 5:28 PM, Joseph Gray <jgray at zianet.com> wrote:

>
> Is the programmable FE-5680A suitable to replace the 12.8 MHz
> reference in a Midland XTR? If so, where do I feed the rubidium into
> the circuit


The long term characteristics of the Rb are very good.  But short term a
crystal oscillator might be better.   You can have the best of both if you
phase lock a crystal oscillator to the Rb.

This whould give you something more like the GPSDO where the 10MHz output
is from a crystal but there is a control on the longer term drift.  You'd
have a "Rubiidium disciplined XO."

You still need access to some kind of "standard" like from GPS so you can
calibrate the Rb.   Your best bet would be to build a GPSDO that runs
directly at the desired 12.8Mhz.  Most off the shelf GPSDOs run at 10Mhz so
this is a good reason to DIY.

-- 

Chris Albertson
Redondo Beach, California