60 kHz (2022)

Historical context & “American-ness”

• Some argue WWVB and similar systems reflect a classic “can‑do” U.S. engineering era (trains, telegraph, moon landings, Voyager).
• Others push back: radio time signals were proposed and implemented in multiple countries (e.g., Eiffel Tower, DCF77 in Germany, MSF in UK). It’s seen more as an engineering inevitability than a uniquely American idea.
• Thread notes early U.S. Navy time signals but also earlier European ideas; who was strictly “first” is treated as ultimately unimportant.

Station operation, outages & coverage

• WWVB is run by NIST; two antennas normally operate at 60 kHz.
• One antenna was damaged by high winds in April 2024, reducing power and coverage; repairs are planned but exact timing uncertain.
• Users report that because clocks often sync only once daily and can take days to catch a signal, continuous high uptime is less critical in practice.

Modulation, bandwidth & 1 bps

• WWVB uses 60 kHz carrier with amplitude reduction at each second; symbol length encodes 0, 1, or a framing mark (IRIG‑style).
• This yields about 1 bit/s. People emphasize this is a design choice for extreme robustness and simple decoding, not a hard physical limit.
• Discussion covers Shannon limits, antenna resonance, and how faster modulation would broaden spectrum and raise power/complexity requirements.
• Comparisons are made to longwave broadcast, submarine VLF comms, spread‑spectrum (GPS), and potential emergency data piggybacking.

Devices & user experience

• Many “atomic” wall clocks, alarm clocks, and wristwatches (Casio, Citizen, etc.) rely on WWVB/DCF77 and are praised for zero‑maintenance accuracy.
• Time zone and DST handling in the U.S. is messy; some clocks use local switches and offsets, though the WWVB code does include DST bits.
• One comment (disputed by context of the thread) claims U.S. time sync is “done via GPS, not radio signals.”

Alternatives & frustrations

• People lament that modern appliances still require manual time setting and often lack even simple NVRAM or battery backup.
• Suggestions: routers or standards like Matter broadcasting local time; NTP on home routers; using GNSS‑based timing and alert services.
• Concerns include interoperability, spoofing (neighbor broadcasting wrong time), cost, and power draw (e.g., GPS receivers).

Hobbyist & educational angle

• Several mention decoding WWVB/DCF77 as an ideal starter project with SDRs, sound cards, or microcontrollers and cheap receiver modules.