Monday, February 16, 2009

The transition has begun: WEAU (NBC 13 Eau Clare, WI) switches to all digital

At around 12:34PM this afternoon (Monday 2/16/09) Eau Clare's NBC WEAU 13 shut off both their analog and digital channels (formerly ch. 39). They moved their digital channel from channel 39 to ch. 13. and should be broadcasting at 26KW. Reports are in that it is up and running.

As has been stated before, WKBT 8 (CBS LaCrosse, WI) and KTTC 10 (NBC Rochester, MN) will be switching tomorrow. WKBT will be moving from ch. 41 back to ch. 8 and KTTC will be moving from ch. 36 back to ch. 10.

Keep re-scanning those channels, folks.

UPDATE: From all that we've gathered, WEAU is extremely weak. Many viewers who got a perfect picture on WEAU analog can not lock WEAU-DT. It seems as if there's a major issue with the station it self. As always, we'll keep you posted on the station. Check out the latest developments for your self on the AVS Forum's LaCrosse/Wausau, WI thread.

Saturday, February 14, 2009

Understanding Subchannels and the DTV channel system

I just realized that information about the physical digital channels might be confusing to the average person, so let me try and explain how the channel system works.

We know for a fact that two things cannot occupy the same space at the same time. Right? Same is true with radio signals. You can't broadcast analog and digital on the same physical channel at the same time. Thus, every full power station is currently broadcasting a digital channel on a different physical than their analog. After stations cut their analog signal, some will move their digital channel to their old analog channel (ie, KTTC moving from 36 back to 10), some will stay on their current digital channel (ie, KXLT FOX 47 staying on 46), and some will move to a completely new channel (not in this market, though).

Obviously, this would create a mess if viewers had to completely re-memorize their channel lineup and stations had to change all their branding to match their digital channel. For this reason, the digital TV standard allows stations to broadcasting a little thing called remap data. This tells the tuner which channel to display it as. For example, KIMT-DT tells your digital tuner (converter box, TV, whatever) "display me as 3-1 and 3-2). Without this piece of information, it would be 42-1 and 42-2. In fact, it has been reported that KIMT's equipment malfunctioned once and the channel came up as 42-1 and 42-2 for a few hours until the engineering staff fixed it.

So why do I need to care about physical channels again? For antenna selection. If you have a VHF only antenna (ch. 2-13), you will no longer get ch. 3 because it is actually on ch. 42. Also, when troubleshooting it's really handy to go into manual tuning and look at signal levels of stations which are too weak to actually decode.

Subchannels. Digital TV isn't so much TV standard so much as a standard to transmit a fixed amount data, be it television, audio or data. TV stations can allocate their bandwidth (19.4 Mb/s) for different uses. For example, KAAL-DT allocates all of their bandwidth to channel 6.1 (ABC) which allows for high quality high definition video and 5.1 surround sound. KTTC-DT on the other hand still broadcasts in HD on 10.1, but uses a portion of their bandwidth for standard definition CW on 10.2. Meanwhile, KSMQ splits their bandwidth into four Standard def channels (15.1,.2,.3,.4).

Wisconsin Public Television used to have an arrangement where they had five subchannels, four of which were SD and one HD. During the daytime, the four SD subchannels would broadcast programming while the 5th sub would display a message notifying viewers when the channel would start broadcasting. At said time, three of the SD channels would cut programming and display a message notifying viewers when the channel would be active again, while the HD channel and one of the SD channels had programming on them. This is a case where the station's channel bandwidth allocations were automatically reconfigured.

[It should also be noted that every station uses a tiny amount of that bandwidth for channel re-map information, guide data, ratings, their callsign, etc.]

Stations can also broadcast audio only channels, encrypted subchannels and datacsts. While audio only channels have not seen much use, there was a company (USDTV) that bought bandwidth from local TV stations where they broadcast a few cable channels to viewers with USDTV boxes and subscriptions. The company went bankrupt a few years ago, and so far as I know nobody uses this feature anymore.

Digital stations can have up to 99 subchannels and the standard allows for remap channels 1-99. There has been talk of national translator networks, such as TBN or 3ABN using one remap channel across the entire country for consistency. In the Twin Cities, Twin Cities Public Television (tpt) owns two channels (KTCA and KTCI). KTCA will be on channels 2.1 and 2.2, while KTCI will broadcast on ch. 2.3 and 2.4.

DTV Transition Delay and the Rochester Market

If you haven't heard lately, Congress passed a bill delaying the digital transition until June 12th, 2009. But some stations are still shutting off the analog on February 17th as originally planned.

Here are the plans for the Rochester/Austin/Mason City market:

KIMT 3 (3.1 CBS/3.2 MyNet - Mason City, IA): The station in broadcasting on analog channel 3 and digital channel 42. After transition, they will still be using digital channel 42. Their current plans are to keep analog on the air until June 12th. At some undefined point in the future, the station will increase ch. 42's power from 200KW to 800KW. As it stands right now, KIMT is pretty easy to lock in Rochester.

KAAL 6 (6.1 ABC - Austin, MN): Their currently broadcasting on analog channel 6 and digital channel 33. As has always been the problem with KAAL, their tower is southwest of Rochester, while all the other stations are south of the city. This creates an issue with antenna aiming. KAAL's digital station is also rather weak in the valley. To remedy this situation, KAAL is acquiring KTTC's ch. 36 facility when they vacate it on February 17th. For the time being, KAAL will simulcast the digital channel on both ch. 33 and 36 until they eventually increase the output power of the ch. 36 facility, when they will presumably end broadcasting on ch. 33. As far as the author knows, the termination date for analog ch. 6 has yet to be announced (we'll know in a few days).

KTTC 10 (10.1 NBC, 10.2 CW - Rochester, MN): The station is currently broadcasting on analog channel 10 and digital ch. 36. At approximately 1:35PM on Tuesday the 17th, both analog and digital will go off the air and then resume broadcasting at around 3:30, using digital channel 10 (at 20kw). This should give better coverage than ch. 36.

KSMQ 15 (15.1 PBS, 15.2 Mhz Worldview, 15.3 (PBS) Create, 15.4 (PBS) tpt-MN - Austin, MN): KSMQ broadcasts analog on 15 and digital on ch. 20. The analog 15 tower is located near Austin, while digital 20 is located on the FOX47/KTTC-DT 36(soon to be KAAL-DT 36) tower, which is almost directly south of the city. Their digital channel stay unchanged throughout the transition and they have announced plans to cut analog on June 12th.

KYIN 24 (24.1 IPTV Digital, 24.2 IPTV Plus, 24.3 IPTV - Mason City, Iowa): The station's analog ch. 24 will remain online until June 12th, as with all other Iowa Public Television (IPTV) stations. Their digital station is located on the KIMT-DT tower, but is probably the hardest in-market station to receive in Rochester (due to lower elevation and output power).

KXLT 47 (47.1 FOX - Rochester, MN): FOX 47's analog channel is 47 and their digital is 46, both are on the same antenna and presumably broadcast from the same antenna. They will be cutting analog 47 on the afternoon of Feb. 17th and their digital signal will remain unchanged.

K56HW 56 (TBN - Rochester, MN): This TBN low power translator is located on an FM radio tower a few miles east of the city. They've filed paperwork with the FCC for a digital channel 39 allocation. Since the station is a low power channel, it does not yet have to comply with a transition deadline. Presumably, the station will cut analog and move to digital sometime in the 2009-2010 timeframe. The station also has to go online after WEAU moves their digital channel from 39 back down to ch. 13. TBN also has to upgrade a number of translator stations all throughout the US.

K58GC 58 (3ABN - Rochester, MN): This 3ABN low power translator is located on the same FM radio tower as TBN 56 is. They have also filed paperwork with the FCC for a ch. 51 allocation. Again, this should happen this year or possibly even next year, as the little network has a number of other translators in need of upgrades.

What this means for you: Re-scan your channels on February 17th/18th, as KTTC will move from 36 to 10 and KAAL will begin simulcasting on ch. 36 and ch. 33. Until the power increases on KIMT and KAAL-DT 36 come, it's about as good as it's gonna get. This means most likely that Rochester viewers will be able to get all market stations (with the possible exception of KYIN-DT) with an indoor antenna or small attic antenna.