-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Mark Sims
Sent: Wednesday, August 19, 2009 8:56 AM
To: time-nuts@febo.com
Subject: [time-nuts] Accurate 1 pps signals
Know where the heck you are down to a gnats ass and get that location
into the unit with full accuracy. Errors in the saved antenna
position from its true position have a definite effect on the quality
of the output. Ideally have the antenna location surveyed in WGS84
coordinates.
OK.. just what is a gnat's ass in actual SI units?
It's small..
Is it a standardized unit drawn from physiology (like the yard or foot,
relative to King John's physical dimensions, or the cubit)
Is it a traditional term for some other standard unit (e.g. a "barn" being
1E-24 cm^2 or a shake being 1E-8, both being from early nuclear weapons
development, and essentially a rounded value for some useful size:
cross-section for a nuclear reaction, and generation time for fission,
respectively) (I understand from some casual googling that the gnat's ass
is used by machinists to refer to a tenthousandth of an inch/tenth of a
mil, although none of the machininsts I know use the term. They talk in
tenths when being quantitative, and have somewhat earthier terms when
talking qualitative)
What I did find with google was interesting.. I didn't know that gnat's
ass as a term for very small dated at least back to Aristophanes, although
the lines 160-164 in Clouds are still qualitative, not quantitative
(narrow, thin/subtle: stenos, leptos)
Next up, we need to decide which species of gnat is being referred to..
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