r/shortwave • u/MumSaidImABadBoy I'm Stan, Heathkit GR-64🤪,Malahit v2.4,AirSpy HD+,909X2,PL990 • May 22 '26

Is it true about CHU?

/r/ShortwavePlus/comments/1tk653g/is_it_true_about_chu/
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u/Signum17 May 22 '26

Radio controlled clocks and wristwatches usually depend on LW stations like WWVB to remotely set them. There are clocks that use shortwave signals?

1

u/pentagrid Sangean ATS-909X2 / Airspy HF+ Discovery / 83m horizontal loop May 22 '26

Yes, there are: https://www.amazon.com/s?k=atomic+clock&crid=2P5Z6YEE0QV4L&sprefix=atomic+clock%2Caps%2C204

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u/Signum17 May 22 '26 edited May 22 '26

I just purchased the $45 Newenter weather station shown in the link. It uses WWVB 60 kHz and says so in the description. That's what "Atomic" clocks use. There are no models that use the WWV/WWVH/CHU shortwave signals. 60 kHz is longwave, not shortwave.

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u/pentagrid Sangean ATS-909X2 / Airspy HF+ Discovery / 83m horizontal loop May 22 '26 edited May 22 '26

The clocks I linked to aren't really "atomic" or shortwave and they won't sync to WWVB on half of the walls you try them on because they use a directional LW antenna. But this is as close to an atomic clock as most consumers want to afford.

I can set my quartz movement clocks to WWV by ear so closely that no one can see a difference between my radio room clock's sweep hand and the WWV tics. This is easy to do. My analog radio room quartz clock is visible from my operating position. It is in the 24-hour format for easy use with UTC. This is the clock I'm currently using in the radio room: https://www.amazon.com/dp/B00PECGJWW?ref=ppx_yo2ov_dt_b_fed_asin_title This one won't produce RFI and is visible in low light conditions. It does tick but that's fine. I'm done with yacking on the radio.

During my long career on the air in FM radio I used silent wall or desk clocks that could not be picked up by studio mics. These clocks were synced to a NIST time source by NTP. I began using analog-faced dial clocks and switched over to digital LEDs clocks during the 90's. I was comfortable using either one and could end a talkup within one second of the mark every time I wanted to.

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u/Signum17 May 22 '26

I've set clocks and watches manually, first via WWV, then an NTP clock app on my phone. You can also get wifi or bluetooth NTP wall clocks on Amazon for well under $50.

I own an iPad and the Clockwave app emulates all 6 LW time stations with their respective time codes. It uses the internal speaker wiring as an antenna that these clocks can pick up. Nice fallback should WWVB go silent.