CHU contact

[M Lombardi]

Regarding CHU, I know they have faced budgetary constraints in the past, like all of the other HF time signal stations. So this is not entirely surprising.

However, it might be worth writing directly about our use of CHU to Dr. Marina Gertsvolf.  She is an excellent scientist and a thoughtful and considerate person.

https://nrc.canada.ca/en/corporate/contact-us/nrc-directory-science-professionals/marina-gertsvolf

73,

Mike, K0WWX 

[Mark Braunstein]

One of the problems with CHU is that it is not readily detectible in the western parts of Canada. In the western regions, people have been relying on WWVB to provide high-latitude coverage. Since WWVB is a US facility, there are sovereignty issues with Canada being dependent on the US for its public services. 
CHU (radio station) - Wikipedia

[Western Canada signal coverage]

Canada is now focused on NRC TimeLink as a service to provide high accuracy time signals. Dr. Gertsvolf is the POC for this effort, so it would be helpful to reach out to her office to learn more about their plans for precision time dessemination. Interestingly, when I click on the link for "High-throughput and Secure Networks Challenge program" I see that the program is also ending in June 2026.. 

High-throughput and Secure Networks Challenge program - National Research Council Canada

This might be a good opportunity for HamSci to revisit the use of commercial shortwave broadcast stations as a signal source for ionospheric measurements. The stability requirements (per FCC rules) for commercial stations is defined in this standard (around 10Hz).

https://life.itu.int/radioclub/rr/ap02.pdf

This is a VERY OLD standard, written in the days when transmitters only utilized ovenized oscillators. That said, there may be stations today that are employing GPS disciplined oscillators. Perhaps HamSci should send out a survey to HF broadcasters, explaining what we are trying to achieve with the personal space weather stations, and ask for performance data. 

WWV has a tolerance of 2E-11. CHU has a tolerance of 5E-12. What is the frequency tolerance of HamSci stations leveraging Leo Bodnar references? 

73,

Mark Braunstein WA4KFZ

[Bruce Crandall]

GPSDO claims 1x10exp-12.

Sorry to hear about CHU.

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73

[Phil Karn]

In my experience, broadcast stations rarely do anything they're not legally required to do. I wouldn't count on any of them having high accuracy carriers without careful verification.

Phil

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