[time-nuts] Conditioning Rubidium Oscillators

Bob Camp kb8tq at n1k.org
Mon Mar 14 16:10:58 EDT 2016


Hi

Yes indeed, the ionosphere is *not* predictable day to day so no matter what you saw yesterday, today will be different. Tomorrow likely will be different as well. Two bumps a day (at least) and even during the day they aren’t certain to be the same. 

Since it is a “space weather” determined thing, with L1 only, all you can do is guess at confidence levels. The real answer is to go to L1/L2 or L1/L2/L5 and at least reduce the level of the problem. You can also do some coordinated things at L1, but then you no longer have a stand alone device. You are part of a network and reliant on a data flow from it.  You are also dependent on that network’s data being more accurate than the item you are trying to discipline. 

Bob

> On Mar 14, 2016, at 2:37 PM, Lars Walenius <lars.walenius at hotmail.com> wrote:
> 
> I read this but couldn´t understand why this is superior to the PI-loop with a pre-filter?
> 
> http://ptfinc.com/wp-content/uploads/2016/03/App_37_RubContol-Rubidium-Control-%E2%80%93-A-Different-Approach.pdf
> 
> Anybody can say why? Even if regression is very useful the limitation of the GPS and ionosphere will be the problem?How much better is it reasonable to get??
> 
> Lars
> 
> 
> Från: GandalfG8--- via time-nuts<mailto:time-nuts at febo.com>
> Skickat: den 3 mars 2016 22:00
> Till: time-nuts at febo.com<mailto:time-nuts at febo.com>
> Ämne: [time-nuts] Conditioning Rubidium Oscillators
> 
> I'm sure I won't be the only one receiving newsletters from Precise  Time
> and Frequency Inc, but I thought it worth mentioning their latest  white
> paper as it offers some thoughts on the conditioning of  rubidium standards via
> RS232 control.
> 
> "Rubidium Control - A Different Approach" can be found here....
> 
> http://ptfinc.com/resources/
> 
> A very basic registration is required but I've always found their mailings
> to be interesting and informative whilst never being intrusive, and
> there's always an unsubscribe option anyway.
> 
> Please not that I have no affiliation whatsoever, just passing on something
> I found interesting.
> 
> Regards
> 
> Nigel
> GM8PZR
> 
> 
> 
> 
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