This kind of thing reminds me of my earlier days I was into ham radio. I was in Japan, so I'd calibrate TS520 with JJY signal. For more than 10 watts, law required "precise frequency measurement equipment", which meant 100KHz Crystal Oscillator. Not temp compensated or oven'd. Just a naked 100KHz AT cut (I think) generator.
If I could, I would do Loran, too but there's no one left transmitting. It's just that over-the-air transmission has nostalgia built in for me.
Thank you for the QST article. That certainly is an impressive piece and fine piece of engineering. I'll have to read them few times over and come up with something similar in function. Since frequency of concern is so low, I'm thinking there could be some software assistance to simplify the hardware quite a bit. Or, I could extract just the PPS and drive something else. I tend to feature creep quite a bit, so I will have to be careful.
In time of internet though, I'm really not sure if WWVB has too much future in it. I heard there could be an issue with running the station due to congressional budget? Times sure have changed! I'm much older and parts are much smaller, too.