Digital TV channel question

[magnadan]

Maybe this has been asked, but I can't find it.

WCVB-TV in Boston was on analog channel 5. Digitally it's on channel 20, but displays as virtual channel 5.

Is it possible for a station that was on, for example, analog channel 48 to choose to display themselves as virtual channel 3?

Channel 3 was never used in Boston. Could that station give itself a perceptually better spot on the "dial" by becoming "Boston's New Channel 3"?

 

[tripinva]

They could, right up until the FCC cites them and orders them to display as 48-1.

- Trip

 

[magnadan]

So virtual channel that is displayed must be authorized by the FCC?

 

[tripinva]

In theory. I'm not sure that it's strictly enforced for low-powered digital signals. I know a full-powered station tried to map to 4-1 and was told they could not use that by the FCC.

- Trip

 

[w9wi]

So virtual channel that is displayed must be authorized by the FCC?

The ATSC digital TV standard includes a standard for selecting "major* virtual channels". To vastly oversimplfy, this standard requires that a DTV station which once had an analog signal must use their old analog channel number as their major virtual channel. Since WCVB once had an analog signal on channel 5, they must use virtual channel 5. ** Analog channel 48 must use virtual channel 48.

This standard is incorporated by reference in the FCC regulations, so it has the same force of law as the rest of the regs.

Reports have it that compliance is not universal and the FCC isn't being particularly active at enforcing it.

Fundamentally, the point is to ensure major virtual channels are unique within a TV market. By using the old analog channel, it's not necessary for the FCC or any other agency to maintain a database of virtual channels to ensure uniqueness; uniqueness is automatic if the rules are followed. There's no technical reason analog channel 48 can't choose to use major virtual channel 3, but if analog channel 66 also chooses to use major virtual channel 3, we have a problem -- two channel 3's.

(in practice most digital TVs will have, well, two channel 3's. Punch in 3-1 and you'll get the one on the lowest RF frequency (which scanned in first); hit channel-up and you'll get the other one. It is however possible to imagine some TVs will receive only the channel 3 on the highest RF frequency -- will overwrite the other ones during the scan.)

_________________________________________________

*"major" being the first part of the channel number -- the "5" of "5.1". The part after the dot, the subchannel, is the "minor virtual channel".

** There are additional provisions covering stations that never had an analog signal.

 

[willcail]

Isn't majority of tv stations uses their virtual channels instead of their actual VHF/UHF channels? The only stations I know that are using their new RF channels for their idents in Ohio are WHIZ DT and WMFD DT.

 

[kenrayc]

Isn't majority of tv stations uses their virtual channels instead of their actual VHF/UHF channels? The only stations I know that are using their new RF channels for their idents in Ohio are WHIZ DT and WMFD DT.

KAIL Fresno -originally analog 53 ,DTV channel 7 , virtual channel 7.1.

 

[avtosalon]

WNYZ-LP New York - originally analog 6, DTV channel 6, virtual channel 1-1

WCIU-TV Chicago - originally analog 26, DTV channel 27, virtual channels 23-1, 26-1, 26-2, 26-3, 26-4, 26-5, 26-6, 48-1

They seem to be bending the rules because 23-1 is identical to 26-2, and 26-3 is identical to 48-1. The exact same programming is mapping to 2 different channel numbers, twice.

Also, how can a station be allowed to map to virtual channel number 1-1? I thought channel 1's were last used was 1948. Also, can the hardware (both the transmitter and receiver) accept a channel that maps to 1-1?

 

[w9wi]

WNYZ-LP New York - originally analog 6, DTV channel 6, virtual channel 1-1

WCIU-TV Chicago - originally analog 26, DTV channel 27, virtual channels 23-1, 26-1, 26-2, 26-3, 26-4, 26-5, 26-6, 48-1

They seem to be bending the rules because 23-1 is identical to 26-2, and 26-3 is identical to 48-1. The exact same programming is mapping to 2 different channel numbers, twice.

Also, how can a station be allowed to map to virtual channel number 1-1? I thought channel 1's were last used was 1948. Also, can the hardware (both the transmitter and receiver) accept a channel that maps to 1-1?

I think the following excerpt from the A/65C standard explains why what WCIU is doing is legal. One can reasonably assume the use of virtual channels 23 and 48 is properly coordinated as the analog stations on those channels are co-owned with WCIU.

7) A broadcaster may include in the transmitted multiplex programming originating from a
different licensed broadcaster and use the major/minor channel numbers of the original
broadcast if the major/minor channel number combinations are coordinated in the local
broadcast area to avoid conflicts. The coordination process is beyond the scope of this
document.

Virtual channel 1 is not legally available to any station for just that reason: it wasn't a valid analog assignment and isn't a valid digital assignment.

It is, however, technically acceptable to use virtual channel 1:

short_name
The major_channel_number shall be between 1 and 99.

Receivers built to the standard will be able to properly receive a "Channel 1" station. Really it would probably be harder to write the software to reject channel 1 than it is to accept it.

(Minor virtual channels -- the part after the dash -- are also supposed to be limited to 1-99 for DTV and audio-only broadcasts. However, I've heard from a viewer in California who's seeing a LPTV station use three-digit minor virtual channels & it's working...)

 

[willcail]

I don't know if any DTV allows its users to directly look at the virtual channel map. The virtual channel map goes from 1.1 to 999.99. If the virutal map find a station within the 2 to 36 and 38 to 51 then it will get the virtual station ident. I do know a low power station in Cincy Ohio broadcast their virtual ident on one of their sub channels as WKRP.

 

[OhioMediaWatch]

Isn't majority of tv stations uses their virtual channels instead of their actual VHF/UHF channels? The only stations I know that are using their new RF channels for their idents in Ohio are WHIZ DT and WMFD DT.

I haven't been down there with a digital tuner recently, but I believe WMFD uses 68-1.

68-2 is the simulcast of their analog LPTV sister WOHZ-CA 41, which mostly runs a weather information screen.

The NBC affiliate in Lima, WLIO, uses virtual 8-1, and 8-2 for the simulcast of analog LPTV "Fox Lima" (WOHL-CA 25). WOHL now has a digital LPTV Class A at 35, former RF home of WLIO's analog signal, and I think they use 35-1 and 35-2 for "CBS Lima" and "ABC Lima".

 

[tripinva]

(Minor virtual channels -- the part after the dash -- are also supposed to be limited to 1-99 for DTV and audio-only broadcasts. However, I've heard from a viewer in California who's seeing a LPTV station use three-digit minor virtual channels & it's working...)

KAXT-LD has since moved the audio subs down to 1-13 through 1-20 down from 1-101 through 1-108.

- Trip

 

[willcail]

At nights when I'm able to pick up WHIZ DT their local events calander they do show the station call letters and below it the number 40. With WMFD DT when I'm visiting my sister and tune to WMFD they ID themselves during their newscast as WMFD DT12. They still display their virtual channel as 68.1. Why move their to a VHF channel and not to a another UHF channel is strange.

 

[mjlarochelle]

I mentioned in another thread, that an NBC affiliate near Waco, Texas formerly on analog Channel 6 but now on Digital Channel 9 is not only mapping to Channel 9, but has even rebranded to reflect the change.

It appears in Canada, there are no specific rules on virtual channels. Some digital stations after signing on did not map to the analog channel; for a period of time CHCH/11 in Hamilton was showing up as 18-1 before finally being changed to 11-1. According to TV Fool (but not Wikipedia), CJMT/69 in Toronto is mapping its digital signal to 14, which is their cable channel position in Toronto and some other cities. And CKXT Toronto's full-powered digital repeaters in London (RF 19) and Ottawa are reportedly mapping to Channel 52, the analog channel in Toronto. For the record, the London station was supposed to be on Channel 26, but the owners opted not to bother with an analog transmitter.

 

[Sammi Brie]

Re WCIU and 23:

23 originates from a different feed (RF 39, WWME), and 48 might too (WMEU). In that case, 26-x is not mapping to 23-x or 48-x at all.

 

[tripinva]

23-1 and 48-1 are being mapped to the same 26-2 and 26-3 feeds. WMEU-CA does not currently have its own digital signal, while WWME-LD has 23-2 through 23-8.

- Trip

 

[w9wi]

I mentioned in another thread, that an NBC affiliate near Waco, Texas formerly on analog Channel 6 but now on Digital Channel 9 is not only mapping to Channel 9, but has even rebranded to reflect the change.

Technically illegal but probably won't be prosecuted as it's not likely to result in a conflict.

It appears in Canada, there are no specific rules on virtual channels. Some digital stations after signing on did not map to the analog channel; for a period of time CHCH/11 in Hamilton was showing up as 18-1 before finally being changed to 11-1. According to TV Fool (but not Wikipedia), CJMT/69 in Toronto is mapping its digital signal to 14, which is their cable channel position in Toronto and some other cities. And CKXT Toronto's full-powered digital repeaters in London (RF 19) and Ottawa are reportedly mapping to Channel 52, the analog channel in Toronto. For the record, the London station was supposed to be on Channel 26, but the owners opted not to bother with an analog transmitter.

Haven't read the Canadian rules (actually I don't know where to look) but I strongly suspect they theoretically apply the same A/65 standard. That standards document covers all the data tables in an ATSC broadcast (not just the virtual channel rules) and I can't imagine Industry Canada would rewrite them.

However, it's up to them how strictly they enforce the virtual channel provisions. Given the massive consolidation in the OTA TV industry in Canada, I'd imagine virtual channel conflicts are unlikely and it's probably not necessary to enforce this part of the standard very tightly.

_________________________________________________

...when I'm able to pick up WHIZ DT their local events calander they do show the station call letters and below it the number 40.

...formerly on analog Channel 6 but now on Digital Channel 9 is not only mapping to Channel 9, but has even rebranded to reflect the change.

A station can show whatever channel they want on the actual video and/or audio. The A/65 mapping rules apply only to what's transmitted in the DTV data tables. I would suggest it would be a bad idea for WHIZ to brand itself as channel 40 if it's actually using virtual channel 18 like it's supposed to. (I might guess WHIZ isn't using virtual channel 18 like it's supposed to...)

_________________________________________________

KAXT-LD has since moved the audio subs down to 1-13 through 1-20 down from 1-101 through 1-108.

That's certainly a lot more standards-compliant. Now all they have to do is fix that major virtual channel number!

Dennis Smith/WTFDA was able to receive the audio subs on 101-108 but I wonder if the station found other receivers, built to standard, wouldn't deal with 3-digit minor virtual channels?

 

[Tim L]

One day several months back when there was a DX opening in the Canton, Ohio area I picked up WHIZ-TV and it did map as Channel 18-1

 

[tripinva]

That's certainly a lot more standards-compliant. Now all they have to do is fix that major virtual channel number!

I'm told this mapping was approved by the FCC.

- Trip

 

[Bob E. Nelson]

I mentioned in another thread, that an NBC affiliate near Waco, Texas formerly on analog Channel 6 but now on Digital Channel 9 is not only mapping to Channel 9, but has even rebranded to reflect the change.

Technically illegal but probably won't be prosecuted as it's not likely to result in a conflict.

In fact, KCEN's PRM for the change from channel 50 allotment to 9 specifically mentioned the mapping to channel 9.
Here's the section from MM Docket No. 01-46, RM-10046:

``Moreover, Channel 6 states that viewer identification of a VHF channel 9 operation will be augmented by the fact that KCEN's analog and digital operations would be in the same frequency band.''