[time-nuts] New NTBW50AA

Bob Camp lists at rtty.us
Sun Sep 8 16:40:27 UTC 2013


Hi

Yes indeed you should get below (thus the sub) the numbers I indicated. At the point I made the comment, he was at 10X that level.

Bob

On Sep 8, 2013, at 12:32 PM, Said Jackson <saidjack at aol.com> wrote:

> Bob,
> 
> Sorry, but an ADEV of 2ns/s at 1s is pretty bad drift for a GPSDO or even a free running low cost TCXO..
> 
> I think a TCXO based unit should be in the 5E-011 to 1E-010 range and a good OCXO unit should achieve better than 5 E-012 at 1s. Even a cheap $150 Thunderbolt can beat the latter easily.
> 
> Remember that a 1s ADEV doesn't measure static frequency error, it measures how the frequency varies from second to second. So 2E-09 at 1s means the frequency is going up and down about +/-1ppb or more every second.
> 
> Thats quite unstable even for the worst references or oscillators out there.
> 
> Something is not working right if Dave sees 10E-09 at 1s...
> 
> Bye,
> Said
> 
> Sent From iPhone
> 
> On Sep 7, 2013, at 18:14, Bob Camp <lists at rtty.us> wrote:
> 
>> Hi
>> 
>> A reasonable ADEV for tau =1 is in the sub 2.0 x10^-9 range (or 2,000e-009).
>> 
>> Bob
>> 
>> On Sep 7, 2013, at 7:27 PM, "quartz55" <quartz55 at hughes.net> wrote:
>> 
>>> Thanks Mark, yeah, I think I'm getting the hang of this thing.  The ADEV is down to 1.032e-008 by this point.
>>> 
>>> I think the red light was on because it was going out of lock, it couldn't find the satellites until I did a survey.  Then things started coming into perspective when it found my position.  At one point the osc was listed as bad.  I just turned it off and started again and it seems fine now.
>>> 
>>> Nothing seems even warm on the board with 30VDC going into it.  That brick I had, I couldn't get the voltage out of it, so I canned that one.  I think I can find a smaller supply than I've got though, this one is an old 10A 12V linear regulated supply that the regulator went out in.
>>> 
>>> I haven't had this much fun since the pigs ate my little brother.
>>> 
>>> Dave
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