[time-nuts] WWV Doppler Shift

[Tom Van Baak]

> That was the first time that I had seen an xy plot of WWV versus a
> stable crystal oscillator.  It is even worse than I thought.  I had to
> look up FRK to see that it is a rubidium standard.  I talked to Jim
> Maxton the chief engineer of WWVB many times around 1995. 

An xy cycle of WWV is just 200 ns, about 80x shorter than the 16667 ns cycle of WWVB. So, yes the xy plot in the video seems to jump around a lot, but if that were WWVB it would be 80x less, barely a wiggle.

Does someone have a strip chart version of that video? Or, better yet, a raw data set of WWV (or WWVB) phase over a day or week? How hard would it be to use a hands-off SDR to produce a 5 MHz WWV phase data point every second?

> Ft Collins is at 5,003 ft and clocks there run fast by 1.663·10^-13.
> (g/c^2)/meter) compared to sea level.

Yes, an out-of-the-box cesium clock will be relatively fast by that amount. But NIST (and everyone else) uses UTC, which is based on the SI second, which is defined at sea level (and several other footnotes).

Which is to say that a national clock or radio transmitter (such as NIST, WWV, WWVB, or DCF77, or GPS for that matter) are adjusted in frequency so they tick SI seconds, and adjusted in phase so they align with UTC.

/tvb