[time-nuts] Practical considerations making a lab standard with an LTE lite
kb8tq at n1k.org
Sun Nov 23 17:59:31 EST 2014
Actually that was Bob trying to explain Tom’s plots simply from looking at them. I *think* I got it right, but it’s Tom’s data and his LTE part. Others have commented that Tom’s part looks different than theirs.
Maybe Tom needs a Microsoft Windows Update on his GPSDO firmware :) For some reason the very thought of Microsoft getting involved in something like that makes me shudder…
> On Nov 23, 2014, at 5:33 PM, Said Jackson via time-nuts <time-nuts at febo.com> wrote:
> From the looks of the plots these may be from the first proto unit with early software no? Also was this with the indoor GPS antenna setup?
> The production units with outdoor or windowed' antenna should have significantly improved average performance from the first unit and its early GPS and GPSDO firmware versions.
> Sent From iPhone
>> On Nov 23, 2014, at 14:18, Bob Camp <kb8tq at n1k.org> wrote:
>> There are two plots with activity changing at 300 seconds. The second plot (purple) is the removal of the paper at 300 seconds. The fourth plot (red) is the addition of the paper at 300 seconds.
>> The last plot (green and blue) is ADEV with and without the paper. Blue is ADEV with paper. Green is ADEV without paper.
>> The second to last plot demonstrates the unit meeting 1x10^-9 (peak to peak) frequency stability with the paper over a 1,000 second test. It shows it doing about 5X worse on frequency stability over the same period without the paper. Yes, that’s all with 1 second averaging. Changing the averaging would impact each of the results. It should change their ratio.
>> Again back to the basic question: frequency over what period? Go to a 24 hour average and the results should be terrific. In some systems, that’s a useful number (I guess….). I rarely see people set their counters to an 86,000 second gate time :)
>>> On Nov 23, 2014, at 4:42 PM, Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby at kirkbymicrowave.co.uk> wrote:
>>> On 23 Nov 2014 16:25, "Tom Van Baak" <tvb at leapsecond.com> wrote:
>>>> For plots and photos showing performance with, and without, and with
>>> insulation see:
>>>> The difference is dramatic, especially if you are used to working with
>>> OCXO where this sort of effect does not occur.
>>> What plots are with and without the thermal paper?
>>> I see several graphs, but don't know what is under what conditions.
>>> The second graph shows something fairly significant happening at 300 s. Is
>>> that where you removed the TP?
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