[time-nuts] Time Dilation tinkering

Hugh Blemings hugh at blemings.org
Mon Mar 20 22:38:51 EDT 2017


I've been mostly lurking on the list for some time now and follow with 
interest the many discussions.  Very much at the early stages of my 
time-nut journey, but enjoying it so far :)

I'd like to have a go at re-creating the efforts of Tom (and I gather 
others) in taking a clock up a mountain for a while and seeing if I can 
measure the relativistic changes.

Being based in Australia gives me a couple of challenges, for one we 
don't really do mountains in the same sense as much of the rest of the 
world - so the highest peak I can readily get to from Melbourne is about 
1,600m ASL.  I live at 80m ASL - so a delta of around 1,500m altitude 
and several hundred km drive.

If I do the math correctly that's about 14ns difference per 24h the 
clocks are separated by that altitude. [1]

We also lack quite the same surplus market here as the US, so purchasing 
a Caesium based standard is well beyond my means.

This got me to wondering if a Rubidium based standard might do the trick 
- the Efratom SLCR-101s seem readily available for ~USD$200 mark.

Clearly there'd need to be a bunch of extra gubbins [2] added to the 
10MHz standard to turn it into an actual clock/counter including battery 
backup and so forth.  And would need a pair of everything.

Before I delve too far into the planning, I'd be interested in feedback 
as to whether this style of Rb standard is likely to be up to the task 
of being the core of such an endeavour or not ?

Oh I should add - my plan was to build the systems such that they 
function as nice standalone time/frequency references once this 
experiment is concluded :)

Thanks in advance,

Kind Regards/73,

[1] gh/c^2 x 3600 x 24  Where h is 1500, g and c the usual values :)

[2] I presume at a minimum a counter running at a 5ns or less "tick" fed 
from a frequency source locked to the 10MHz of the Rb standard.  This 
counter would need to be latched for reading from an external signal so 
that it can be compared to the second clock.  Not sure but seems the 
TAPR TICC might have role here :)

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