4 ms·

WWVB is great if you can get the signal -- I have two of those clocks in different rooms, and only one of them synchronizes.

by dgacmu 2y ago

jrockway 2y ago
Newer clocks use the phase modulated signal: https://www.nist.gov/system/files/documents/2017/05/09/NIST-Enhanced-WWVB-Broadcast-Format-1_01-2013-11-06.pdf https://www.nist.gov/system/files/documents/2017/05/09/NIST-... If you have AM-based clocks, you might find that these work better. However, nobody advertises which module they're using, so it's kind of a crapshoot. I specifically bought a phase modulation WWVB receiver and it reliably receives the signal every night. I also have a random $7 clock from Amazon that pretty much synchronizes every night. Living in NYC, this is truly amazing to me; I never ever got the AM signal here.
- creeble 2y ago
  Thanks for that! Didn't know there were two kinds of radios. I have one clock that always works perfectly, syncs after DST 100% of the time. Another that always requires manual reset twice a year, defeating it's purpose.
cvoss 2y ago
It's an incredible feat to me that a single station can broadcast to the almost the entire US, Mexico, and even parts of South America at the right time of day [0]. (I believe this is why many clocks check for the signal overnight.) It's achieved by using an extremely low frequency, at 60 kHz. The antenna is enormous and suspended between 4 towers. [0] https://tf.nist.gov/stations/wwvbcoverage.htm https://tf.nist.gov/stations/wwvbcoverage.htm [1] https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvb https://www.nist.gov/pml/time-and-frequency-division/time-di...
- ghaff 2y ago
  Communication with subs uses ELF/SLF (3-300 Hz) when they're underwater--in the US case from some big communications stations. The coastal VLF stations, like in Cutler Maine are more in the 24 kHz range. As I recall, at one point, there were ecological concerns with the ELF stations but apparently the projects ended up going ahead.

WWVB is great if you can get the signal -- I have two of those clocks in different rooms, and only one of them synchronizes.

by dgacmu 2y ago

WWVB is great if you can get the signal -- I have two of those clocks in different rooms, and only one of them synchronizes.

jrockway 2y ago

Newer clocks use the phase modulated signal: https://www.nist.gov/system/files/documents/2017/05/09/NIST-Enhanced-WWVB-Broadcast-Format-1_01-2013-11-06.pdf https://www.nist.gov/system/files/documents/2017/05/09/NIST-... If you have AM-based clocks, you might find that these work better. However, nobody advertises which module they're using, so it's kind of a crapshoot. I specifically bought a phase modulation WWVB receiver and it reliably receives the signal every night. I also have a random $7 clock from Amazon that pretty much synchronizes every night. Living in NYC, this is truly amazing to me; I never ever got the AM signal here.

creeble 2y ago
Thanks for that! Didn't know there were two kinds of radios. I have one clock that always works perfectly, syncs after DST 100% of the time. Another that always requires manual reset twice a year, defeating it's purpose.

cvoss 2y ago

It's an incredible feat to me that a single station can broadcast to the almost the entire US, Mexico, and even parts of South America at the right time of day [0]. (I believe this is why many clocks check for the signal overnight.) It's achieved by using an extremely low frequency, at 60 kHz. The antenna is enormous and suspended between 4 towers. [0] https://tf.nist.gov/stations/wwvbcoverage.htm https://tf.nist.gov/stations/wwvbcoverage.htm [1] https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvb https://www.nist.gov/pml/time-and-frequency-division/time-di...

ghaff 2y ago
Communication with subs uses ELF/SLF (3-300 Hz) when they're underwater--in the US case from some big communications stations. The coastal VLF stations, like in Cutler Maine are more in the 24 kHz range. As I recall, at one point, there were ecological concerns with the ELF stations but apparently the projects ended up going ahead.