[time-nuts] Solar Eclipse Changed WWV Frequency

[John Ackermann N8UR]

There's a nice article at https://www.spaceweather.com/ about how 
reception of WWV at remote locations was affected by the eclipse, 
specifically Doppler shifts as the reflective layers of the ionosphere 
moved up and down as the sun's energy was suddenly removed.  The work 
cited in the article was part of the HamSci (https://hamsci.org) project 
that I've been part of.

We WWV (and CHU) see Doppler shifts of up to a couple of Hz every 
morning and evening so that in itself isn't unusual.  What was unique is 
the opportunity to observe the shift from day to night propagation and 
back over a few minutes.

Another part of the Case experiment, not mentioned in the article, is 
taking advantage of an even more unique opportunity -- standard time and 
frequency station CHU in Ontario, Canada, was very near the totality 
path  The Case group recruited a number of WebSDR receiver sites that 
experienced totality to monitor the three CHU frequencies (3330, 7850, 
and 14670 kHz) for effects on paths following the eclipse line.  In 
addition to frequency changes, they are looking for changes in the time 
of arrival of the seconds ticks.  The set of KiwiSDR receivers that I 
run in central Ohio contributed data to that project.

A lot of other propagation-related experiments were running as well.  My 
station also saved the entire AM broadcast band as IQ data on disk 
(about 1.1TB total), and we are watching multiple station carriers on 
each channel pop in and out of view around the eclipse peak.  There were 
strong signal strength changes as well as Doppler shifts.

Lots of neat science will come out of all this.

John