[time-nuts] Time Signals on TV signals

[Glenn Little WB4UIV]

It appears that the time information is transmitted in line 21 of the 
analog TV signal.
This is the same line that carries Close Captions in an analog signal.
It further appears that PBS is the major carrier of these time signals.
See : 
http://simson.net/ref/autoclock/Interface-June-01.pdf#search=%27PBS%20time%20signal%20auto%20VCR%20set%27

This may explain why you are having problems.

I do not know how this is handled in the DTV world.

We translate line 21 captions to CEA-608 and CEA-708 captions for out 
DTV transmissions.

See: 
http://ncamftp.wgbh.org/DTV/CEA%20test%20material/Iteration_1/It1.2ReadMe.pdf

This explains a little about the conversion of analog line 21 to DTV captions.

It is possible that you can set your recorder to read 608 captions?

Hope this helps.

73
Glenn
WB4UIV
CE WCIV TV

At 12:52 PM 5/25/2009, Bill Hawkins wrote:
>Aficionados of accurate time,
>
>I have two Panasonic DVD TV recorders, a DMR-EZ27 and 28. They were set to
>automatically sync time to a TV station. This worked fine until a few months
>ago. Now they are on manual time, but, of course, they drift.
>
>Tried to turn automatic time setting back on this morning. The screen says,
>"This may take a few minutes." It still said that 10 minutes later, as the
>busy indicator continued to rotate through three spots.
>
>Gave up on automatic and asked the only group I know that might know.
>
>Why did TV stations stop broadcasting time signals? HDTV requirements?
>
>Could a cable company interfere with the time signals?
>
>Thanks,
>Bill Hawkins
>
>
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