[time-nuts] New NTBW50AA

[Said Jackson]

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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