[rescue] cheap gps for time reference (fwd)

[Dave McGuire]

On July 6, Kris Kirby wrote:
> My father replies:
> 
> All ready checked them out - they basically have an older Motorola PVT-6,
> 6 channel receiver in them.  Its the predisesor to the Oncore's.  Its
> really too much for what it is.  They sold new for around $1200.

  6 channels isn't an issue...this is a stationary device.  But yes, the
receiver is the predcessor to the Oncore, and even that has been out
for several years...but there's a LOT more in that box than the
receiver.  My catalog says $5K (assuming I'm looking at the right
box).

> And people forget something - its not a frequency standard.  Over the
> short term, they do parts to the 10x6.  Only over 60,000 seconds they
> start approaching 10-11 or 12th....

  It's a GPS/PLL stablized OCXO.  (Its oscillator is an HP 10811D, which
is an impressive oscillator by itself.)  That's a frequency standard
by most (if not all) definitions.  It is a long-term standard like a
cesium oscillator...excellent long-term stability, not-so-good
short-term stability.

  This is what's required for the very highest-precision measurements
anyway, since high-testicle-factor timing systems (using
postprocessing and averaging across multiple oscillators) don't really
tell you what time it IS, but what time it WAS, after all the
post-processing.

> Sez the man with a rubidium standard, several crystal ovens, a few TCXOs,
> and about four Oncores, and a Jupiter, IIRC.
> 
> Timing's his bag, baby.

<mineisbigger>
  And I've got two cesium standards, beeyatch.
  Mr. Bill will tell you about my clock if he's so inclined. ;)
</mineisbigger>

     -Dave

-- 
Dave McGuire                  "Needing a calculator indicates that
St. Petersburg, FL              your .emacs file is incomplete." -Joshua Boyd