[time-nuts] Updating the unit of,time: the second.

[Bob Albert]

 Well I have enjoyed time and frequency measurement for many years.  I have no equipment (nor do I expect to get any) that can tell the difference between the current second and the proposed standard.  And at one point I asked if there was a limit on the smallest time interval that could be discerned.
I do remember being impressed with the Collins gear in the 1950s, and wanting one of those 7 foot racks of time standards made by General Radio, the one with the big clock on top.
As the years passed I obtained more and more accurate frequency measurement equipment, including a home made heterodyne frequency meter that outdid the Collins radios.  Then the lousy radio propagation ended my dependence on WWV and I luckily obtained a rubidium oscillator.
But that's about as far as I want to go.  My HP 8657B resolves 1 Hz at more than 2 GHz and it can be set to within a very small error with respect to the rubidium standard.  At this point I see no reason to improve my time and frequency measurement accuracy.
Of course it can be an end in itself, hence the name Time Nuts.  So I propose the question, how many out there have interest in this topic for academic and psychological reasons, and how many actually have a concrete reason to be this precise?  One part per billion isn't a lot.  And some systems require iron clad synchronism such as space exploration and long range communication.  But the average tinkerer probably doesn't need it.
Bob
    On Monday, May 27, 2019, 3:20:24 AM PDT, Dave B via time-nuts <time-nuts at lists.febo.com> wrote:  
 
 Hi.

This from the recent ShortWave Radiogram broadcast, may be of interest.

~ ~ ~

(Snipped stuff about other SI units undergoing a revamp...)

Scientists now have their sights set on updating the unit of
time: the second.

Currently, the second is defined by atomic clocks made of cesium
atoms. Those atoms absorb a certain frequency of light. The
wiggling of the light's electromagnetic waves functions like the
pendulum on a grandfather clock, rhythmically keeping time. One
second is defined as 9,192,631,770 oscillations of the light.

But a new generation of atomic clocks, known as optical atomic
clocks, outdo the cesium clocks. "Their performance is a lot
better than what currently defines the second," says physicist
Andrew Ludlow of the National Institute of Standards and
Technology in Boulder, Colo. Because those optical atomic clocks
operate at a higher frequency, their "ticks" are more closely
spaced, making them about 100 times more precise than cesium
clocks.

Ideally, the length of a second should be defined using the most
precise timepieces available. A switch might happen in the late
2020s, Ludlow says.

The change to the kilogram's definition was carefully
orchestrated so that it wouldn't affect normal people: A kilogram
of flour still makes the same number of biscuits. Any change to
the second will be similarly coordinated.

So, sorry, there'll be no chance to squeeze any extra seconds
into a day.

https://www.sciencenews.org/article/kilogram-just-got-revamp-unit-time-might-be-next

~ ~ ~

So, perhaps a host of surplus cesium clocks on the market at some point?

73

Dave B G0WBX.

-- 
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