DFW Daylight Savings Time Transition and ATSC

Spring 2025

Daylight savings time begins on 9 March which means that stations should begin sending PSIP data to that effect on 10 February. The details on how this process should be managed are in ATSC A/65, Annex A and FCC regulations require that all exceptlow power stations follow the standard. But they have a poor recordof following the standard.

8 February

A few stations were two days early:

WFAA (RF 8)

KERA (RF 14)

KTXD (RF 23)

KPXD (RF 25)

KFAA (RF 30)

This is the same as saying that daylight savings time begins on 9 February. Which will cause any receiver that uses this data to display schedule data with the wrong times. And change displayed time on the 9th. These stations really should know better.

9 February

More stations decide to screw it up today:

KFWD (RF 9)

KAZD (RF 31)

Fortunately this wasn't quite enough to trigger whatever majority algorithm is used by my DVR.

Waiting till late in the day is still wrong:

KDTX (RF 21)

10 February

Finally the day arrives when things are supposed to happen and a few stations manage to do it correctly.

KTXA (RF 18)

KXAS (RF 24)

KDTN (RF 29)

KDAF (RF 32)

KUVN (RF 33)

KDFW (RF 35)

KXTX (RF 36)

Leaving one full power station (KDFI) that has done nothing so far.

11 February

Something very wierd is going on with KDFW today:

KDFW (RF 35)

The DST change information was dropped for a while and then returned. I also noticed some of their usual wierdness with program guide data. Perhaps related.

17 February

KDFI, which had given DST a miss, added the required data this evening. At pretty much the same time, KDFW (common operations for the two channels) also restored this data. Perhaps as a result of a detailed email I sent last week (pretty much in the blind as they list no email address for technical problems on their web pages) after two phone calls went unanswered.

KDFI (RF 27)

KDFW (RF 35)

The good news is that KDFI restored the program guide data which had been missing for over a week. The bad news is that it vanished from KDFW.

10 March

Daylight savings time change day. Since the DFW market doesn't span a time zone boundary, this should happen at 2AM CST, sharp. Naturally not everyone does it correct.

KERA decided to do it at 1AM:

KERA (RF 14)

(All times in these plots are in Central Standard Time.)

KDTX had to screw it up in a unique way. Dropping the change data last night at 8PM. Which messes up displayed schedule data. Then at 2AM they set the DST flag.

KDTX (RF 21)

A few stations performed the change at 2AM as required: WFAA, KFWD, KTXD, KPXD, KFAA, and KAZD. More waited until 3AM: KTVT, KXAS, KDFI, KDTN, KDAF, KUVN, KDFW, and KXTX.

Taking the prize for doing it the worst way possible is KHPK, a low power station. They never provided any DST data but when the time came, the error in the broadcast time data went from ~3619 seconds to -19 seconds.

KHPK (RF 10)

Summary

It sure would be nice if TV stations could get something as basic as time correct so that I could stop doing this. I suspect that ATSC 1.0 will be shut down in favor of ATSC 3.0 (which pretty much assumes that the receiver has an Internet connection) before that happens.

History

Since I no longer have the space limitataions with my Earthlink pages I can make data from previous transitions available here rather than rely on the Internet Archive.

ATSC Monitoring

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