sowny.net | The Southern Ontario/WNY Radio-TV Forum


You are not logged in. Would you like to login or register?

December 4, 2020 12:27 pm  #1


Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

Forgive my ignorance, of which I admit I have a lot. But engineering was never one of my areas and I'm hoping someone here can tell me what a decision issued by the CRTC on Friday means. 

The Commission granted several Corus over-the-air stations permission to "multiplex" their signals. That means in various markets (but not Toronto) Global stations will be able to broadcast other TV channels from a single transmitter. For example, in Peterborough, CHEX will be able to not only broadcast its own signal, but also add CIII (Channel 27) from Peterborough, along with CKWS from Kingston.

Ottawa's Channel 6 will remain but also add the same CKWS signal from Prescott. 

There are others, including two based in B.C. 

My question - do these go out as subcarriers of the main station or are they just using their transmitters to send out these stations on separate channels? (Like WIVB does with WNLO - one on Channel 4, the other on Channel 23?) I'm curious if these are the first examples of someone taking advantage of subcarriers in Canada or is it just a more efficient use of a transmitter? 

I suspect the latter, since the company told the Commission it was urgent. "Corus clarified that it has requested authorization to broadcast multiplexed signals in order to continue providing the same over-the-air programming that is currently broadcast by seven transmitters that Corus might otherwise have to shut down, in which case that programming...will no longer be offered at all." 

The reason this matters is that Canadian TV stations either have not tried to or haven't been allowed to take advantage of subcarriers in this country - unlike the U.S. where there are hundreds of them. I'd love to see this happen, but it's not likely even if the CRTC allowed it, because OTA station owners Bell and Rogers don't want you watching off an antenna and would prefer you subscribe to their cable or satellite services.

Whatever the case, I think this may be a first for Canada. I'm just hoping someone here can tell me exactly what it means. 

The Affected TV Stations

 

December 4, 2020 1:40 pm  #2


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

Hi RA

To your question, in digital TV, each service is not really a "subcarrier" (like you might have in FM radio) but rather each is part of the overall digital signal.  Each service has its own "quality" parameters.  Typically the "main" channel is given more quality "bits" than a so-called sub-channel.

By "multiplexing" a number of "channels" Corus WILL be able to shut down transmitters, which ultimately is the goal I am sure (one way or another).  For example, they have a "Global" transmitter in Peterborough (CHEX-DT), a "Global" transmitter north of Cobourg (CIII-DT) and a "Global" transmitter (CKWS-DT) in Brighton.  The CHEX-DT Peterborough transmitter is on VHF channel 12 and covers a wide area.  By doing this, they can shutdown the Cobourg and Brighton sites.  This is a result of Corus acquiring the Global channels from Shaw Media in 2016, flipping CHEX and CKWS to Global programming and the resulting overlapping of transmitter signals.  Viewers in the coverage areas will still be able to receive each independent service, albeit from a common transmitter.

As noted above, in the Corus case, I suspect each multiplexed service will have the same number of "bits" assigned and therefore they will all have the same general picture quality.

It's the same scenario for the Ottawa and the BC markets.

This is a perfect use of digital transmission and the ability to "multicast" different services.  We should have been doing it long ago in Canada.  Smart move by Corus.

I expect CTV to follow in similar markets with CTV and CTV2 services.
 

 

December 4, 2020 2:20 pm  #3


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

So if I understand this, these won't be subcarriers like WGRZ's Channel 2.1, 2.2. and 2.3. They'll all be separate TV stations, but all coming from one transmitter. And yes, if it doesn't affect reception, it makes a lot of sense. In addition to WIVB and WNLO, I believe Channels 7 and 17 in Buffalo are from the same stick. 

Oh, and one more thing. The CRTC document notes that all the stations will be broadcasting at 720p HD, as opposed to 1080i.

Thanks for the explanation.

     Thread Starter
 

December 4, 2020 2:46 pm  #4


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

RadioActive wrote:

So if I understand this, these won't be subcarriers like WGRZ's Channel 2.1, 2.2. and 2.3. They'll all be separate TV stations, but all coming from one transmitter

well, sorta yes and yes.  This process is EXACTLY the same as your WGRZ example that has been used in the States for years.  All the "separate" Global stations will be "subcarriers" (to use your term).  When tuning to the multiplexed signal from Peterborough you might see (for example) 12.1 (CHEX-DT),  27.1 (CIII-DT-27), and 11.2 (CKWS-DT-1)

RadioActive wrote:

and one more thing. The CRTC document notes that all the stations will be broadcasting at 720p HD, as opposed to 1080i

720P is easier to compress than 1080i and is more bandwidth efficient and that is probably why they are moving to 720P.

 

 

December 4, 2020 3:00 pm  #5


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

I've often wondered: can you actually tell the difference between 720p and 1080i? It seems to me they all look pretty good to most human eyes. Why would you opt for one over the other?

     Thread Starter
 

December 4, 2020 3:38 pm  #6


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

Yes I can. On smaller monitors the difference is insignificant

 

December 4, 2020 3:57 pm  #7


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

RadioActive wrote:

I've often wondered: can you actually tell the difference between 720p and 1080i? It seems to me they all look pretty good to most human eyes. Why would you opt for one over the other?

Great question and it has to do with "frame rate", or in other words, how often the image is displayed on the screen.

We all know (right?), just like film, video is a series of still images, displayed fast enough to make the brain think its motion (and oh ya, and there is no such thing as yellow, but I digress.... ).

Believe it or not, this stuff goes back to the early days of TV so there's lots of "stuff" here.

1080i (the "i" is for interlace - the thing that old CRT picture tube TV's used) has a higher resolution than 720p which makes it better (?) for images such as newscasts, interview shows and documentaries.

720p (the "p" is for progressive - the way modern screens work) has a higher frame rate (how fast the image is displayed) than 1080i which makes it better (?) for sporting events that typically have lots of motion.

So, if you are a TV station, you might choose your flavour (1080i or 720p) based upon the type of programming you have.

Oddly enough, today's flat panel "TV's" are inherently progressive scan (p) and therefore must convert 1080i to progressive for display, which can have a negative impact on the image.

Can you see the difference?  It depends on what you are looking at.

1080i is so 1990.....



 

 

December 4, 2020 4:15 pm  #8


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

Thanks for the explanation. I always learn something new here. Now about that 4K video...

     Thread Starter
 

December 4, 2020 4:37 pm  #9


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

Hopefully no one loses out on any OTA coverage with this change. 

I am also hoping that other networks follow suit with using their mux capabilities. It would be good to see CTV2, Radio-Canada, and Omni TV rolled out to other parts of the country via a subchannel of their sister networks. 

 

December 4, 2020 6:30 pm  #10


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

There is 2 ways they can do this...   

For the sake of appearance independence they could use the same transmitter and assign digital channel number to one station, and another channel for another.   Technically it's the same frequency channel, but appears on each persons TV as a different channel number.      

True subchannels tend to give you 2-1, 2-2 and so on.   Typically this is done if they relate, to the main channel or if they are keeping it under the same call letters, like most US subchannels with satellite programming.   They don't require unique licenses to do this, in the US. 

Technically the same thing between the two, but I have a feeling they won't want to merge licenses and want to keep the independence between the two, should something happen to one over the other.   I'm mostly shocked CTV and CTV2 haven't done in areas they overlap.   (Barrie/Toronto for example) or CBC and ICI. Even Omni 1 and 2.  You can get 2 good quality HD signals on one transmitter, or multi SD full screen stations.

 

Last edited by radiokid (December 4, 2020 6:37 pm)

 

December 6, 2020 10:37 pm  #11


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

We have come a long, long way from the days where one transmitter = one license = one programming stream = one "station."

In a sense, Canada was already a bit ahead of US regulators: in the US, in the analog era, every transmitter required its own separate license. Some ("translators") might not have originated their own programming, but they still had individual licenses that could be sold or moved or transferred or what have you, independently of the station they relayed. By contrast, Canada was quicker to separate "license" and "transmitter" into separate categories - CHCH had its original channel 11 license in Hamilton, and then added more transmitters in London, Ottawa, cottage country, etc., all under the CHCH license. 

Then came digital TV and its ability to broadcast multiple program streams over a single transmitter. The "display channel" can be whatever you set it to be in the encoder - it's literally just a forwarding address that tells the tuner in your TV which video and audio streams to pull out of the overall data stream and display to you. 

Licenses still exist on paper and still matter for some aspects of the broadcast regulatory scheme south of the border. Because WNLO is a separate "full-power" license from WIVB, it enjoys certain rights, especially with respect to asserting must-carry rights on cable and satellite - it's entitled to those rights in a way that a "subchannel" of the WIVB license wouldn't be. 

(And yet - WNLO could start using 4.2 as its virtual channel and would still be considered a separate license with its own must-carry rights; those go with the license on paper and not with the virtual channel number.) 

Another twist down here involves "low-power" licenses and channel sharing. You can have a station that held a low-power analog license but has entered into a channel-sharing agreement with a full-power station, like the NBC owned-and-operated station in Boston. "Low-power?" Only in its license status (which means it's not entitled to force must-carry on cable or satellite) - but not in its on-air reality, because it now channel-shares with WGBX, one of the public TV stations with a full-power signal that's the equal of the other big full-power stations in town. 

Confusing? You bet. It's a new reality that a lot of US broadcasters are still learning how to manipulate to their advantage. There are "full-power" stations that sold their spectrum and are now channel-share tenants on low-power signals, "low-power" stations that operate as channel-share tenants on high-power signals... every imaginable permutation of breaking the old one transmitter/one program stream/one license model.

Oh yeah - "low-power" licenses don't count against TV ownership caps here. Neither do subchannels that aren't under separate licenses. So when the MyNetwork outlet in Syracuse, WNYS, got caught in a potential ownership-cap issue when its parent company was sold (which eliminated a previous grandfathering), it gladly surrendered its license - but nobody in Syracuse noticed, because "43.1" stayed on their TVs, only now as a subchannel (no separate license) of the Fox station, WSYT. Same programming, same virtual channel, identical signal quality, but now it's legal when it wasn't before. 

Weird times. 

 

December 7, 2020 8:09 am  #12


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

RadioActive wrote:

So if I understand this, these won't be subcarriers like WGRZ's Channel 2.1, 2.2. and 2.3. They'll all be separate TV stations, but all coming from one transmitter. And yes, if it doesn't affect reception, it makes a lot of sense. In addition to WIVB and WNLO, I believe Channels 7 and 17 in Buffalo are from the same stick. 

Oh, and one more thing. The CRTC document notes that all the stations will be broadcasting at 720p HD, as opposed to 1080i.

Thanks for the explanation.

As far as Channels 7 & 17 using the same transmitter....nope. WKBW's is in Colden, while WNED's is on Grand Island.

 

December 7, 2020 8:20 am  #13


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

Are you sure? A few months ago, I spoke to an engineer from WKBW and another from WNED and they both told me they were on the same tower. Did that change after the repack? I thought it was WIVB and WNLO that were in Colden.

     Thread Starter
 

December 7, 2020 9:45 am  #14


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

Both WKBW-DT and WIVB / WNLO have their transmitters located in Colden, N.Y. (separate sites/towers).

WGRZ-DT is close by with their transmitter/tower being located in Sheldon / South Wales N.Y.

 

December 7, 2020 12:55 pm  #15


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

Here's the most comprehensive explanation I can give of who's gone where in Buffalo during the repack:

WGRZ: Has always operated from its longtime site in South Wales (southeast of Buffalo). Stayed on RF 33 in the repack. 

WIVB: Analog in Colden (south of Buffalo), original RF 39 digital in Colden, initial pre-repack (2017) signal sharing with WNLO from the WNED tower on Grand Island on RF 32. Final post-repack signal on RF 36 shared with WNLO back at the WIVB tower in Colden. (Initially at lower power from a side-mounted antenna there, then at full power beginning June 2020.) 

WKBW: Has always operated from its own tower in Colden, just south of the WIVB site. Moved from RF 38 to RF 34 in the repack. (I think there had been some discussion with WKBW about channel-sharing with WNED at one point, but nothing ever came to fruition.)

WNED: Has always operated from its own tower on Grand Island. Moved from RF 43 to RF 31 in the repack. 

WNLO: Analog on the WNED Grand Island tower, pre-repack digital on Grand Island RF 32, shared with WIVB since 2017, final post-repack digital shared with WIVB at the WIVB Colden tower, on RF 36. 

WUTV: Analog on its own Grand Island site (just west of WNED), pre-repack digital from Grand Island on RF 14, temporary post-repack digital under STA on RF 32 from the former WNLO facility on the WNED tower (April-September 2020), permanent post-repack digital at the WUTV Grand Island site on RF 32. 

WNYO: Analog from Cowlesville, Wyoming County (east of Buffalo), pre-repack digital from Cowlesville on RF 49, post-repack digital (first under STA and since Sept. at full power) from the WUTV Grand Island site on RF 16.

WPXJ: Analog and pre-repack digital (RF 23) from Pavilion, Genesee County (halfway between Buffalo and Rochester), post-repack digital from the former WNYO Cowlesville site on RF 24. (No more indoor antenna reception in Rochester for us!)

WBBZ: No changes in the repack - its digital signal on RF 7 is the same as it's always been, from an old AT&T microwave tower north of Springville, the southernmost of the Buffalo-market sites (except for WNYB down in Arkwright, near Fredonia.) 

 

December 7, 2020 1:51 pm  #16


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

fybush wrote:

WKBW: Has always operated from its own tower in Colden, just south of the WIVB site. Moved from RF 38 to RF 34 in the repack. (I think there had been some discussion with WKBW about channel-sharing with WNED at one point, but nothing ever came to fruition.)

Perhaps this is what the engineers I talked to were referring to. Maybe they thought it was a done deal. I remember one of them (I think it was the WNED rep) saying if you point your rotor at WKBW, you'll get us, too. Or something like that. That may be where I got the idea that they shared the same tower. 

fybush wrote:

WNLO: Analog on the WNED Grand Island tower, pre-repack digital on Grand Island RF 32, shared with WIVB since 2017, final post-repack digital shared with WIVB at the WIVB Colden tower, on RF 36.

One of my biggest regrets about the repack. WNLO was once one of the best Buffalo signals into Toronto. Not anymore. Both WIVB and WNLO are now often hit and miss, depending on the weather. It's about I'd say a 70/30 split, with it coming in most of the time - but not always.  

fybush wrote:

WPXJ: Analog and pre-repack digital (RF 23) from Pavilion, Genesee County (halfway between Buffalo and Rochester), post-repack digital from the former WNYO Cowlesville site on RF 24. (No more indoor antenna reception in Rochester for us!)

Comes in better than ever after the repack. Unfortunately, there's not much to watch on it!

fybush wrote:

WBBZ: No changes in the repack - its digital signal on RF 7 is the same as it's always been, from an old AT&T microwave tower north of Springville, the southernmost of the Buffalo-market sites (except for WNYB down in Arkwright, near Fredonia.) 

The one station I wish we could get. If I'm lucky, I can pull it in twice or three times a year in the summer on a good day - and it usually doesn't last long. I love to get both ME TV and Decades - but, alas it's not to be!

That's quite a list Scott. Thanks for the trouble of making it. I'm surprised you guys in engineering were able to keep track of it all. 

     Thread Starter
 

December 7, 2020 2:30 pm  #17


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

The biggest surprise of the repack to me wasn't the Buffalo stations. It's actually one that should be receivable with no problems at all. Yet, I frequently have trouble with Global. Either it doesn't come in at all, or else it breaks up terribly. As most here know, you either get the digital signal or you get nothing - or some digital artifacts. I'm somewhere in the middle of all of those. 

To get the Channel 41 signal clearly, I have to move my rotor significantly. But when I do that, I lose many Buffalo signals, most especially WIVB and WNLO. Since I watch those more often than Global, I tend to leave the antenna set for the latter two. But I like to occasionally monitor Global News and it's very annoying having to make an adjustment for a signal that's local and supposed to be pretty strong. (Plus I have to remember to move the rotor back to the original spot, something I often forget to do.) 

Does anyone else experience this issue with this particular station?  

     Thread Starter
 

December 7, 2020 3:04 pm  #18


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

Weird. I get Global with an indoor antenna.


 
 

December 7, 2020 3:33 pm  #19


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

RA, your problems are likely overload from the CN Tower.  You might try using a 6db attenuator.  They can be bought on Amazon.ca for approx $14 - package of 2.  On some sets, I could not get Ch. 2 or Ch. 4 buffalo without significant rotation of the antenna. (approx 20 degrees west of buffalo).  After inserting the attenuator I am able to receive 2, 4, 7 well on the TV's that have the attenuators.   I believe you are using a preamp?  Once you get too much overload from the CN Tower, it can impact reception of local signals i.e. Global.   My experience was to remove pre-amps after the final repack this fall and reception was restored.
BTW, the Global signal from the CN Tower is very strong in terms of ERP - 58 kw I believe..  So I would lean towards the theory of severe overload on your antenna/pre-amp system.
 

 

December 7, 2020 3:59 pm  #20


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

RadioActive wrote:

Does anyone else experience this issue with this particular station?  

It's possible you're actually getting too MUCH signal, depending on how close you are to the CN Tower. DTV tuners don't like getting overloaded, and it can manifest itself as a loss of signal. You might try to use less antenna - maybe even as little as a bent paperclip - and see if it helps matters any.

If it does, you can get tuned traps (Tin Lee right there in Toronto makes good ones) that can reduce the signal level for Global (RF 17, if memory serves) that will reduce the signal level for just that station while still letting other signals through at full amplification. 
 

 

December 7, 2020 4:07 pm  #21


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

Thanks to both of you for the suggestions. I will look into them. As a further diagnostic (and why I think you may both be right), I just checked the signal strength vs. the signal quality reading on my PVR. The strength is a perfect 100%. The quality is only 5%, and that fluctuates as the signal blinks in and out. If I turn the outdoor rotor, it improves to 100% on both readouts. Odd that it only happens on Global and none of the other locals, which are otherwise terrific. 

Now if you could just suggest some magic solution that would let me get a watchable signal for WBBZ here in northern North York, I'd be a happy guy!

     Thread Starter
 

December 7, 2020 8:58 pm  #22


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

RA, I did quite a bit of work this fall to try and acquire WBBZ.   I put up a high-band yagi - which had plenty of gain.  It's an excellent antenna   I also tried  the antenna with with/without pre-amps.   I have a pretty good line-of-sight to their transmitter - and if you look at their coverage map on rabbit-ears info, I should have had a fairly reliable signal based on my location.  I couldn't even get a signal reading on "normal" days, though I see them 3-4 times a year when tropospherics are up.  I think it's a combination of things, including CFTO being first adjacent on Ch. 8.
I also think that their actual coverage is many miles south of predicted coverage...and that could be a function of their actual antenna (vs projected) pattern.  I was quite surprised that I did not have any measurable signal, on a variety of tuners/receivers/dvrs etc.   One last point.  When I looked at the predicted signal levels for WIVB, WKBW and WGRZ, versus WBBZ, there should have been a somewhat reliable signal for WBBZ.  (all the Buffalo U's (51, 49, 29, 23/4, 17,  7 and 2 are excellent and solid over 99% of the time at my site.   Given the fact that I have 4 UHF antennas mounted at different points on my rooftop and each delivers comparable results for WIVB, WKBW and WGRZ - and I used those spots for the test of the VHF High-band antenna, my conclusion is that there's simply no signal  getting into midtown toronto from WBBZ.  Next spring I will try with a tuneable trap to notch out CFTO.  
 

 

December 7, 2020 9:20 pm  #23


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

Let me know how that goes, although I suspect it probably won't work. Most of the Buffalo stations are pretty good where I am at the edge of North York (with the occasional exception on 4 & 23) and a 40' antenna with a UHF and an old VHF head on a rotor. 

The only way I can conceive of getting WBBZ here would be to get an illegal subscription to Dish Network or Direct TV using an address in Buffalo and watching it that way, since they're obligated to carry all the local over the air signals. 

Expensive, not legal and probably not really feasible. 

Maybe one day they'll move or upgrade their signal. Until then, ME TV will never be my TV! (Although Channel 49, ironically really IS MyTV!)

     Thread Starter
 

December 8, 2020 2:21 pm  #24


Re: Will These Be The 1st Cdn. OTA TV Subcarriers Or Something Else?

This is a visual of the WBBZ tower...  a former AT&T micro relay station.

Small side mounted 4 bay antenna on one of the support legs. Below the first deck level of the tower (due to the KS horns, and wave guide still being in place).

Lacks the height and the real power to punch thru....





 

Last edited by Glen Warren (December 8, 2020 2:24 pm)