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60 kHz (2022)

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Re: 60 kHz (2022)

#41

Post by metaphor »

wglb wrote: post #18
tkzed49 wrote: post #6

the bandwidth is just enough to broadcast a single digit of binary every second. I'd be interested in some more context on this. I think it's pretty clear that you can encode more than 1bps in a 60kHz signal, but I'm curious how the encoding was chosen. There's some more detail on it here: https://en.wikipedia.org/wiki/WWVB#Modulation_format The WWVB 60 kHz carrier, which has a normal ERP of 70 kW, is reduced in powe…

By "atomic" clocks (for example https://www.amazon.com/Crosse-Technology-WT-3129B-Atomic-Ana... ), and older brands of watches. I think there are also older industrial applications using this technology to syncronize.

> ...and older brands of watches.

Modern watches too, e.g. Casio digital watches marketed as integrating their "Wave Ceptor"/"Multi-Band 6" feature[1].

I still use a 17-year-old (batch code[2] 202A327G) G-Shock GW-530A (predecessor of this active offering[3]) that syncs with WWVB every morning several hours before dawn.

[1] https://en.wikipedia.org/wiki/Casio_Wave_Ceptor

[2] https://shockbase.org/watches/batchcode.php

[3] https://www.casio.com/us/watches/gshock/product.GW-M530A-1/

Re: 60 kHz (2022)

#42

Post by MadnessASAP »

joshellington wrote: post #29
pavel_lishin wrote: post #25

Earlier quoted context omitted.

Plus you have to defend yourself from the neighborhood kid who thinks that it'd be a laugh riot to randomize everyone's clocks at 5:15 in the morning.

That would have absolutely been myself, wardriving at 16 (back in the early aughts). Sending nonsensical print jobs and then setting everyone’s clocks to 4:20.

I'm in my mid 30s and I still regularly tell unattended Google Homes and Alexa's to set an alarm for 4 AM.

Re: 60 kHz (2022)

#43

Post by sllabres »

If I think about time an American nowadays the first thing that comes into my mind is GPS. What WWVB or DCF77 (and JJY) was back then is now GPS timing capabilities. Much higher precision but of course a higher complexity for the receiver. [1]

I don't know about WWVB and JJY but the German DFC77 is not only AM modulated but FM too allowing for a better accuracy.

[1] https://www.hopf.com/dcf77-gps_en.php#chapter3

Re: 60 kHz (2022)

#44

Post by V99 »

lxgr wrote: post #40
anaidioschrono wrote: post #30

Earlier quoted context omitted.

I love these clocks! I've had a few in every house I've lived in, from all along the West Coast and Midwest.

Since the equivalent European signal I'm familiar with only covers a single timezone, with unified DST rules, I'm curious: Do these usually have an adjustment button for a time zone offset? And how do they handle DST – do they have an "I'm in Arizona (but not in the Navajo Nation), leave me on standard time" switch?

They usually have an offset and a DST option. So in Arizona you'd choose -7/Off, and never touch it again. In Colorado you'll have to toggle DST twice a year manually, because it doesn't know the rules for when it starts/ends.

Re: 60 kHz (2022)

#45

Post by metaphor »

mmastrac wrote: post #22
khaki54 wrote: post #7

I can picture a room full of engineers in ties, wearing pocket protectors full of implements, chain smoking cigarettes while coming up with this one.

More likely a radio nerd, John Alvin Pierce, that was just really good at radio and obsessed with oscillators ( https://ieeexplore.ieee.org/document/60675 ) that inspired a group of distinguished government-employed engineers and scientists. In fairness, there _might_ be a pocket-protector in this picture of them but it's a bit blurry. Actually, yes, there definitely is. No cigarettes, however: https://www.ncbi.nlm.n…

Quick image link fix...spaces in URL broke auto-hyperlinking:

https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/t...

Re: 60 kHz (2022)

#46

Post by russdill »

tkzed49 wrote: post #6

the bandwidth is just enough to broadcast a single digit of binary every second. I'd be interested in some more context on this. I think it's pretty clear that you can encode more than 1bps in a 60kHz signal, but I'm curious how the encoding was chosen. There's some more detail on it here: https://en.wikipedia.org/wiki/WWVB#Modulation_format The WWVB 60 kHz carrier, which has a normal ERP of 70 kW, is reduced in powe…

Reminds me of encodings for IR remote controls such as RC5

Re: 60 kHz (2022)

#48

Post by Aloisius »

anyfoo wrote: post #2

> I’m not particularly patriotic, but this kind of thing feels particularly American. ??? America has no doubt done some very remarkable things (the moon landing, the first backward compatible color TV standard), but I don't think this is a notable example of that. I think everyone in Europe was familiar with even wristwatches getting the time from "airwaves". At least in Germany, watches were a very common thing sin…

> I think everyone in Europe was familiar with even wristwatches getting the time from "airwaves". At least in Germany, watches were a very common thing since the 80s

Not the 80s. The first radio controlled wristwatch came out in 1990 (Junghans Mega 1).

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