Self-setting Clocks

Self-setting clockThere is confidence in knowing your wall clock is self-setting and self-correcting. Pull it out of the box, and within a few minutes the time sets itself. That is if the clock can receive the 60kHz signal broadcast by WWVB from Ft. Collins, Colorado. However, the signal only is reliable in the continental United States, and not all the time even there. If you take your clock with you to another country, the time updates are not received and the clock begins to drift.

WWVB began broadcasting Coordinated Universal Time (UTC) in 1962. The VCR debuted in 1972 to report the time as 12:00am. Over time the VCR became self-setting by taking the time from the TV signals. However, like WWVB the time reference used by the VCR was not available everywhere. Since the 1980s the Network Time Protocol has helped many networked computers become accurate. Now that wireless networks are common in the home, our clocks should be able to connect to update the time.

old style clock faceThe downside is different countries have different frequencies and the various wireless network solutions will eventually become outdated and retired. Wireless networks are not a long term solution since clocks do not get replaced as often as computers. With a self-correcting grandfather clock for example, it could be passed from generation to generation. Eventually the time reference used by the clock would disappear and the clock would drift. Although the clock mechanism can be replaced occasionally; that is not very satisfying.

Setting a wall clock automatically seems like it should be a trivial technology. However, communications technologies change rapidly. Also, each country specifies different frequency ranges for their wireless communications. Even the cell phone doesn’t fit the bill as a clock reference since the protocols in use are changing rapidly and would be obsolete well before the clock stopped working. I guess Ford Prefect was right, “Time is an illusion, lunchtime doubly so.”.

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2 Comments on “Self-setting Clocks”

  1. Laura Says:

    Ah, more rapid obsolensence in our lives. Not to mention that the US congress changed when Daylight savings is, and this needs to be programmed in.

    That being said. I like the self-setting clocks. I have confidence that it is the right time.

  2. Wayne Says:

    Actually, daylight savings time info is broadcast by WWV, not programmed into simple receivers. My watch, which syncs to WWV, had no problem with the DST changes.

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