[time-nuts] Timing Distribution in Mountainous Terrain
jimlux at earthlink.net
Fri Sep 10 05:17:51 UTC 2010
Ralph Smith wrote:
> On Sep 9, 2010, at 8:01 PM, Rick Karlquist wrote:
>> I would like to point out that the environmental sensitivities of
>> the 5071A are unmeasureable, and the measurement threshold is
>> far below 5.8E-14. I would estimate that the 5071A (and ONLY the 5071A
>> among commercial clocks) could get the job done provided that you could
>> compare its frequency to GPS to the stated accuracy. This would
>> be using the 5071 as a secondary standard. You still need to
>> deal with the short term stability of the 5071A, depending on
>> your system needs. JPL uses H masers as flywheels.
> I would imagine the cost of a 5071A per radio station would make the check writers swallow hard, and adding an H Maser into the mix would really get their attention. Especially if you need redundancy.
there's also the possibility mentioned earlier of using a lower quality
standard at each station and flying (driving) a higher quality clock
(5071) around often enough to keep them trued up.
If it's far enough in the future.. Hg ion traps have a lot of
potential.. smaller, lower power, etc. than Cs
I think, though, that some sort of self calibrating array using the
target of interest is a better scheme.. multiple receivers at each site
separated by some distance. Getting milliradian angular resolution is a
piece of cake.
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