[time-nuts] Disciplining a Rubidium with a Thunderbolt.

[Dr. David Kirkby]

On 07/12/11 02:15 AM, Tim Tuck wrote:
> Hi all,
>
> Just wondering how many people have used John Miles work @
> http://www.ke5fx.com/tbolt.htm, or similar, to discipline a rubidium
> oscillator and if so...
>
> 1. what was the RB of choice ?
> 2.have any measurements of phase noise etc. been published on such a rig ?
> 3. Are there any published how-to's etc. available ?
>
> I'd like to build such a beast as my lab standard so any help appreciated.
>
> thanks
>
> Tim

I'm no expert on this, but I believe that the rubidiums have poorer phase noise 
than crystals, so unless holdover performance is an issue, there is no advantage 
in using a rubidium over a crystal as long as GPS lock is maintained at all times.

The Stanford PRS-10 rubidium looks to be quite nice, as it has a 10 MHz crystal 
to give good phase noise and also the rubidium for medium term stability. It can 
be disciplined easily, as it has a 1 pps input.

Alas the PRS-10 is not as plentiful (i.e. cheap) as some other rubidiums.

There may be better ways, but a PRS-10 and a timing receiver which outputs 1 pps 
looks to be a relatively easy way to get the short term peformance of a crystal, 
the medium term performance of a rubidium should the GPS get unlocked and the 
long term stability of GPS.

I'm looking for a lab standard too, so I'd be interested in what other replies 
you get. For me personally, for a short term solution, I'm thinking of using an 
undisciplined rubidium.

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