Re: How do auto-set clocks grab the time?

If the OP is still listening to this thread, please post the make and model of the clock you have.

I doubt that it is a battery backed clock, but we should be able to tell with proper information.

donald

donald wrote in news:XvydnerjVJrX4h3anZ2dnUVZ snipped-for-privacy@comcast.com:

Sony ICF-C318 (dual alarm) is the model, mentioned earlier. An even cheaper cousin is the Sony ICF-C218.

The manual says nothing about any receiving device, referring only to a factory "preset" time. That's why I'm differentiating it from loopstick antennas, WWVB, etc.. These cheap auto-set clocks seem to be a recent novelty. Emerson calls theirs "Smart Set."

When a manual doesn't explain something clearly I assume it's lower-grade technology, like a long-life button battery vs. a 9V backup battery. That goes back to my question of how the time is refreshed over months & years. Assist from a 60Hz signal seems logical, but why wouldn't it say so? The manual is written as if owners shouldn't care.

This clock has been consistently fast by 15 to 20 seconds, referenced to my Atomic clock and

If it used a precise signal you'd expect much better.

This model lets you manually set it but it jumps back to the auto setting instantly; another mystery. That's why I can never set it dead-on. I'm not in the mood to take it apart but I may have to!

Jack

Why assume that?

How would that be logical? How does the 60Hz help it know what time it is? When I turn on my Commodore 64, it has a clock that runs off the

60Hz, but it doesn't know it's January 5th, 11:25PM. How could it? How could the clock? Please explain why you think a 60Hz sine wave of 120V RMS contains the local time ?? Describe a circuit that could extract the local time from a 60Hz sine wave. Why haven't devices like TVs and VCRs used this magic before? You could have prevented decades of flashing 12:00 on VCRs.

Again I don't get it. Why would you want to *Set* an *Auto* set clock? What are you basing yourself on to decide *it's* wrong? The atomic clock in the basement?

this device is a clock radio. so it has an am antenna and receiver. it is almost certainly using wwv.

the manual doesn't mention it because wwv is decades old. the manual probably doesn't mention the difference between am and fm either.

alan nishioka snipped-for-privacy@nishioka.com

Not really. They replaced the transmitters and towers a few years ago, so nothing but the building is old.

--
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prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

snipped-for-privacy@netzero.com wrote in news: snipped-for-privacy@c4g2000hsg.googlegroups.com:

I can't logically answer that one, but this clock was only $15. One has to go on gut feelings sometimes.

Not necessarily the local time, but a cheap, well-known way to stabilize it:

See the part where I wrote that it's consistently off by 15 to 20 seconds. It creates a Catch-22 of having a clock that's adequately accurate and instantly-recovering vs. better accuracy through a manual setting.

If you don't know what I mean by an "Atomic" clock these days, I will have to take your other questions with a grain of salt.

Jack

Alan Nishioka wrote in news:fb3704b8-4ade-4559-bf02- snipped-for-privacy@e6g2000prf.googlegroups.com:

"Preset" implies a battery is keeping an internal clock active vs. a received signal. Were it a received signal it would function much the same way an "Atomic" clock does. You power it up and wait a number of minutes until it gets the first solid signal from Colorado.

I am looking for a definitive answer if anyone has it. I could contact the maker but I'm lazy right now.

Jack

It even says in the manual that the clock maintainence battery is a CR-2032 and describes how the clock will behave when the battery runs out. See my earlier reply.

Or off the RDS included on some FM and all DAB broadcasts (the latter

1-2s out of sync with reality).

Regards, Martin Brown