DFW Daylight Savings Time Transition and ATSC

November 2019

Daylight savings time ends on 3 November which means that stations should begin sending PSIP data to that effect on 4 October. The details on how this process should be managed are in ATSC A/65, Annex A and FCC regulations require that all except low power stations follow the standard.

1 October

KDFW gets things off to an early start by setting DS_day_of_month to 1 on 30 September:

KDFW (RF 35)KDFW DST change information

They left the hour at zero so receivers that depend on OTA time data will be an hour off all day. This change seems to have happened at the same time they added a subchannel. (DECADES on 4.2) The also decreased the amount of schedule data from 2 days to 12 hours. Someone was fiddling with the PSIP generator as though they had never seen one before.

A few stations don't bother with the whole DST thing: KHPK (RF10), KBOP (RF20), and KAZD (RF31).

3 October

They aren't supposed to do anything until tomorrow but of course several stations started the transition today. Which will cause some receivers to display time that is off by an hour today.

KXAS (RF 24)KXAS DST change information

KDTN (RF 29)KDTN DST change information

KMPX (RF 30)KMPX DST change information

KXTX (RF 36)KXTX DST change information

KXTX decided to go with a bogus day of month (27).

A couple of stations waited till very late in the day.

KDTX (RF 21)KDTX DST change information

KFWD (RF 9)KFWD DST change information

4 October

This was the day when everyone should have started the process.

KTXA (RF 18)KTXA DST change information

KTVT (RF 19)KTVT DST change information

KUVN (RF 33)KUVN DST change information

5 October

A day late isn't too bad.

WFAA (RF 8)WFAA DST change information

KERA (RF 14)KERA DST change information

KTXD (RF 23)KTXD DST change information

KPXD (RF 25)KPXD DST change information

7 October

One station changed their DST data today. Changing it back again a few hours later and then again shortly after that. I guess they just couldn't figure out what they wanted to do.

KDAF (RF 32)KDAF DST change information

12 October

KXTX changed the day from the wildly wrong 27 to the correct value of 3 today.

KXTX (RF 36)KXTX DST change information

3 November

A mixed bag today. Two stations flubbed the final transition by dropping the day and hour to zero yesterday:

KFWD (RF 9)KFWD DST change information

KDTX (RF 21)KDTX DST change information

Times are in DST. So at 2100 hours they stopped telling receivers of the upcoming change and then changed the DST flag at 2AM. The result would be that the receiver would display time correctly but schedule data during that 5 hour time period would not have taken the DST transition into account. (PSIP schedule data uses GPS time so the display time has to be calculated based on time zone and DST status.)

Some stations completed the transition as expected. Since the DFW market is nowhere near a time zone boundary, DST_status along with the day and hour should change to zero at 2AM (DST) like this:

KERA (RF 14)KERA DST change information

KERA, KTXD, KPXD, and WFAA got it right.

Several more waited a while: KTXA, KTVT, KXAS, KDTN, KMPX, KDAF, KUVN, and KXTX are in this group. While not technically correct it at least shouldn't cause any trouble at the receiver.

Then there are the stations that either didn't bother or flubbed it in creative ways. Like KDFW that is still saying that the transition will happen at midnight on the 1st of the month. Very odd since its sister station (sharing a chief engineer) KXTX did perform the transition this morning.

Leaving two stations signaling that we are still in DST. KDFI and KDFW.

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