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Casio G-Shock time sync radio

gshock.casio.com

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Re: Casio G-Shock time sync radio

#181

Post by cbzoiav »

agos wrote: post #137
cbzoiav wrote: post #136

Earlier quoted context omitted.

The only thing I can think of is if it was widespread it would be a security risk. Not exactly difficult to broadcast a stronger signal with the wrong time. Similar problem with GPS being used for clock sync in mobile/cell base stations in much of the US. You can buy an (illegal) jammer off Ali express and bring down a tower for very little money.

I don't know where you live, but here broadcasting such a signal would mean having the police knocking at your door really quickly. Unauthorized broadcasts are taken very seriously

We're talking something the size of a cell phone that can be powered for days on a battery. Hide it near the cell tower and leave. It takes specialist equipment to locate it so by the time someone has figured out what has happened and either got that equipment in or just done a manual search it's been hours to several days.

Or for some mayhem just stick a few of them under seats on public busses / trains set to activate at the same time.

Re: Casio G-Shock time sync radio

#182

Post by jhoechtl »

exitb wrote: post #132
Gud wrote: post #131

Earlier quoted context omitted.

I have a 15+ years old G-Shock with this feature. When I was in Afghanistan in 2010, I would still occasionally get this signal. I suspect these coverage maps are quite conservative.

I live ~700km from DCF77 and never get the signal indoors. Which is unfortunate in this case, as the watch tries to synchronize at night, when I’m usually at home.

Place your watch away from phone chargers. I live more than 700 km away and get it reliably every night on a small wrist watch once it put my watch away from the phone charger.

Re: Casio G-Shock time sync radio

#184

Post by gregsadetsky »

madengr wrote: post #90
gregsadetsky wrote: post #41

Earlier quoted context omitted.

Thanks for those references! I wanted to see what an SDR radio time signal detector would look like, and looking for "DCF77 sdr python" pointed me in the right direction -> [0] and [1] A bit unrelated question: there are many web SDRs that let you listen to radio frequencies/stations such as [2]. Are there web / Emscripten SDR decoders that run in-browser? i.e. a full browser listening + decoding experience? For exam…

This is mine. Select the timecode decoder: http://kiwisdr.lounix.net:8073/

Amazing, exactly what I was looking for! I've had luck on http://carinthia.proxy.kiwisdr.com:8073/ (the link you posted seems busy right now)

I was able to use the FSK decoder, it worked really well. For those curious, the C-based decoder extensions are here [0]

[0] https://github.com/jks-prv/Beagle_SDR_GPS/tree/master/extens...

Re: Casio G-Shock time sync radio

#185

Post by fomine3 »

Gud wrote: post #179
Ekaros wrote: post #156

Earlier quoted context omitted.

Occasionally isn't good. It either has to work consistently or not at all. If someone has wrong understanding what the time is and their clock goes to "wrong" time occasionally it is bad. And on other hand if marketed people expect such features to work. Even indoors or in basement. Next to window facing right direction in lucky meteorological conditions is tough ask for majority. Geeks will geek out when it works on…

I don't understand your point. My watch was not marketed to function in Afghanistan at all. It was made clear the towers are in the US(IIRC two of them), Berlin and Japan. And I think few people expect their wrist watch to synchronize over radio in a basement... And if they are, they need to understand radio better. There is little drift on my G-shock anyway. Probably it would still be extremely accurate if it hadn't…

Possibly the US military base had radio tower even though it's not their territory?

Re: Casio G-Shock time sync radio

#186

Post by ilyt »

paulmd wrote: post #174
gh02t wrote: post #98

Earlier quoted context omitted.

Damn I had never thought of the possibility that you could easily battery back the clock in a microwave/oven/etc despite being fully aware that it's trivial to do. We get a ton of brownouts and I gave up on keeping the clocks set. I want it.

there's also another compromise, my stove will remember the last time it had AC power but it "loses" however many minutes it was out of power. And that can be implemented purely in non-volatile RAM (some kind of non-volatile CMOS register probably) without the actual piezo timing circuit (the clock itself can run off 60 hz utility frequency timebase). Just update the nvram once a minute. https://en.wikipedia.org/wiki…

That's... weird one. Like, why bother even commiting it to memory if it will be out of date?

Re: Casio G-Shock time sync radio

#187

Post by 19h »

I’m from Germany — we drove to Arizona from California a few years ago and were too late for check in which was super annoying. I got a SEIKO Astron watch that synchronizes the time via GPS after that and couldn’t be more satisfied; it also runs on solar and holds a charge of 6 months for when there’s no sun (i.e. Antarctica). This watch is so precise it’s my absolute time reference. When I’m traveling I keep my Apple Watch at home and only wear the SEIKO; the Apple Watch is pointless anyway if you’re stuck in the desert for more than a few days.

Re: Casio G-Shock time sync radio

#188

Post by bestham »

jansan wrote: post #125
strangattractor wrote: post #74

Earlier quoted context omitted.

Have solar atomic version. Don't wear it much these days. Mostly when I travel. Been on my dresser 2 years collecting dust but gets some sun. Picked it up the other day for a camping trip. It was both charged and had the correct date and time.

The newer ones go into sleep mode until they sense some movement. Each morning when I pick up my GW-M5610U-1 (of course with the titanium mod), the display is blank and then fills with data within a second or so. I really like the feeling that although I hopefully have a few more decades to live, this watch may be my trusted companion for the rest of my life.

It’s not movement but light hitting the solar cell that activates it.

Re: Casio G-Shock time sync radio

#189

Post by JADev62096 »

Ekaros wrote: post #156
Gud wrote: post #131

Earlier quoted context omitted.

I have a 15+ years old G-Shock with this feature. When I was in Afghanistan in 2010, I would still occasionally get this signal. I suspect these coverage maps are quite conservative.

Occasionally isn't good. It either has to work consistently or not at all. If someone has wrong understanding what the time is and their clock goes to "wrong" time occasionally it is bad. And on other hand if marketed people expect such features to work. Even indoors or in basement. Next to window facing right direction in lucky meteorological conditions is tough ask for majority. Geeks will geek out when it works on…

Completely disagree. All clocks and watches have a degree of uncertainty. Even a once a quarter time sync is enough to improve the accuracy. If you want to be sure you have the correct time, then you check and set against a reference source or press the button to see when last received. What is the harm that would be caused by an occasional sync?

Re: Casio G-Shock time sync radio

#190

Post by namibj »

pkulak wrote: post #126
clusmore wrote: post #83

Earlier quoted context omitted.

Note that an integer offset is insufficient. For example, Australian Central Standard time is +9:30 and Australian Central Western Standard Time is +8:45. I have a Seiko watch with a similar feature to this and I don't think it would work well in either of these timezones.

That’s not even enough because different zones observe DST at different times, or not at all. You would have to enter your actual time zone, not an offset, like when you install an OS or something. And then if that zone ever changes, which happens a lot, the clock in your microwave will often, or always, be wrong. So now your microwave needs to be internet connected to download tz databases, and what are we even doin…

Thankfully DCF77 transmits the legal time and date including pre-announcing of skips for the country it operates from: Germany. And for logistical reasons, the time zone extends quite far beyond the country borders. Co-inciding with where you have truly good reception.
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