During the past two weeks I've received a number of questions about PSIP and TSID from stations changing channels on June 12. Even after reading the FCC rules, it may not be obvious what PSIP and TSID tables need to be changed when a station moves to its analog channel or a new channel post-transition. This is because the details are not in the FCC rules, but rather in ATSC Standard A/65C. The FCC rules require stations to comply with the ATSC standard.

So what happens if you are changing your DTV channel on Friday?

The simple answer is, if you had an NTSC license on June 12, you do not need to change anything. Your major channel number will not change. The details are in Annex B of A/65C:

It states that “if during or at the end of the transition period, the RF channel assigned to a broadcaster for digital ATSC broadcast is changed for any reason, the major channel number used by that broadcaster shall not change.”

Thus the TSID is locked to your analog channel and community of license and does not change. Since many stations are moving DTV to their analog channel and several others are switching to new channels, I expect the FCC will release an updated TSID table once the transition is completed.

While the Commission hasn’t indicated what it plans to do with in-core analog channels left over after June 12, one possibility is that they will be auctioned for new DTV stations. These stations won't be able to use their DTV channel number as their major channel, as is the normal procedure for new DTV stations, as this would conflict with the station that had held it as an analog channel.

Annex B also has an answer for this situation.

“If, after the transition, a previously used NTSC RF channel in a market is assigned to a newly-licensed DTV broadcaster in that market, the newly-licensed DTV broadcaster shall use, as his major channel number, the number of the DTV RF channel originally allocated to the previous NTSC licensee of the assigned channel.”

This makes sense, because as the DTV channel of another station in the market, it could not have been previously assigned as a major channel number.

Is channel 88 a valid major channel number? According to A/65C, it is.

The standard says that values for major channel numbers 70 through 99 “may be used to identify groups of digital services carried in an ATSC multiplex that the broadcaster wishes to be identified by a different major channel number.”

For additional information, including information on how to set PSIP for translators and satellite TV stations, review the ATSC Standard Program and System Information Protocol for Terrestrial Broadcast and Cable (Revision C) with Amendment 1. It would be a good idea to take a look at it before June 12 in any event.

Many of the unusual problems I've seen where a station or program is visible on some DTV converter boxes or DTV sets and not others were caused by errors in PSIP.