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Industry Canada puts moratorium on the use of television channel 51

8K views 31 replies 18 participants last post by  roger1818 
#1 ·
In a letter to the CRTC last month, Industry Canada says it has put a moratorium on the use of television channel 51, the current upper limit of the broadcast spectrum band.

The Canadian move follows similar actions by the U.S. Federal Communications Commission (FCC) last August.

Industry Canada says it's taking the action in order to promote the deployment of wireless broadband services in the lower part of 700 MHz (A Block) spectrum.

The department says the decision applies to all regular power and low power TV applications and is effective immediately. The moratorium affects only the applications for new or modification to facilities predicated on increased usage of the spectrum. It does not affect existing regular power or low power television stations on channel 51. Those stations may continue to operate previously authorized facilities.
 
#2 ·
The plan is not to use it to prevent interference, but it is part of the wireless spectrum, channel 50 will have the same effect, and so on.

Time for better utilization of attributed bandwidth, not shuffling around. If all was given to wireless, they'd find new ways to waste it.
 
#3 ·
Technical Articles by Charles Rhodes (TV Technology Mag) re Interference between DTV
and New Cell Phone Freqs in the so-called 700 MHz Band:
http://www.tvtechnology.com/article/cell-phone-dtv-interference-issues-examined/210567
http://www.tvtechnology.com/article/solving-dtv-wireless-broadband-interference-problems/210841

BTW: Ch51 might be helping by eliminating ADJACENT channel interference to Cell Phones,
but as Charles Rhodes points out, there can be significant NEXT ADJACENT
(N+/-1, 2, 3, 4, 5, 6, 7, etc) EMI...esp. anywhere near the DTV Antenna Farms....and
when/if even more UHF freqs are transitioned from DTV to Cell Phone usage, then
EVERY lower channel will be occupied, making it certain that IMD products will fall
on top of the even Newer Cell Phone Freqs....at which point, ALL DTV operations
will be encouraged to move to the VHF Band....just Ch2-13...minus Ch5+6 for FM????
 
#4 ·
The traditional remedy has been to reduce power allotments on frequencies that may interfere with other services. For example, this was done with the low end of the FM band to prevent channel 6 interference. Eliminating use of channel 51 looks more like a claw back. Next up, the channel 51 frequencies will go to cellular services and channel 50 will be eliminated...
 
#5 ·
The way I see it in the future (less then 10 years) they will go after 600MHz too pushing the TV channels lower, then they will go after 500MHz. The spectrum is to valuable a natural resource that it will be sold off in time to the Cell phone companies.

The other question you have to look at is ‘do we really need 51 channels for DTV?’ The answer is clearly no we do not. We have around digital 20+ OTA channels in the GTA… the amount of spectrum they also use could be cut in half, right now, if they were to switch over to MPEG-4, so in the future I’m sure they will be forced over to MPEG-4.

Another idea that comes to my mind when I think about all of this is… do we really need to be sending out Digital TV using one high power transmitter? What if we used a series on low power digital TV transmitters every few miles… the existing Cell phone towers could each be equipped with low power digital OTA ATSC transmitters forming their own cellular TV network. Since Digital TV already uses virtual channeling this would work very well allowing adjacent cells to use different RF channels. This would give great coverage to the end users… you would only need a small indoor antenna to receive the signal for a local cell tower. All you DTV channels would be coming from the one tower. This would also prevent Canadians from receiving American TV if they were also to switch to such a system… and we know our Government will like that idea.

The use of low power transmitters would also take care of any interference problems.

I’m sure in the next 20 years we’re going to see a big change in the way Digital TV is delivered OTA.
 
#6 ·
The IC moratorium on channel 51 makes the Rogers application to move from 51 to 40 look like a good bet. I know that they are not forcing existing channel 51 stations to move but clearing the channel in Toronto fits with the new policy. In a big market like Toronto, why would IC refuse the channel change? I think it's a done deal.
 
#7 ·
We don't have 51 channels available for OTA. 2-13; 14-51 minus 37 and 51. So 48.

And yes, we need that many to prevent interference from other stations.

One high power transmitter is the most spectrum efficient manner of delivering services. Short range transmitters would require more spectrum to reduce interference. And using low power transmitters would increase the cost of providing services: More equipment, more tower rental, etc.
 
#10 ·
Jase,

I guarantee you that they will in fact go after 600MHz and 500MHz when the time comes.

It will be the Cell Phone companies that will dream up this idea of delivering OTA digital TV over their own Cell towers as a way to get that spectrum they will so badly want in the coming future... cost will not be a factor to them because of what they will gain in the long run.

Rogers for example is a Cell Phone company, a Cable TV provider, and a TV station owner… the perfect example of what will come next!

I’ve envisioned so many things about the future that came true… this is something I do see happening.
 
#11 ·
There have been a few stations in the US that have tried what's called a Distributed TV Service. A DTS system is usually the original transmitter with on-channel repeaters in terrain-blocked areas. Interest in such operations has dropped to zero, and grand plans have gone unbuilt.

Distributed low-power transmitters will not be the solution.
 
#12 ·
HDTV101, I have no doubt they'll (wireless providers) demand more spectrum in the future. The problem I have is that they're already sitting on plenty of unused spectrum. One could say they've been hoarding it.

Tux: Existing stations on 51, as Hugh mentioned in his post, won't be affected.
 
#13 ·
Ban on 51

More mismanagement of spectrum.We have 37 blank and have not heard complaints yet cell phones need a buffer while combine them and give 37 back to OTA and leave 51 blank for astronomy.
 
#14 ·
I'm pretty sure neither the FCC nor the CRTC/Industry Canada can change the laws of physics. Channel 37 (608-614 MHz) is kept blank because of specific phenomena that occur in that frequency range. I don't think you can ask the phenomena nicely to relocate to 698-704 MHz and expect it to listen. :)

- Trip
 
#19 ·
Channel 51 is left blank for the future creation of a guard band.

The lower parts of the 700 Mhz will be use for LTE stations with a very high sensitivity.

About the 500 Mhz and 600, dont worry IC have no plan to do like the FCC
. Canada should have plenty of spectrum for upcoming whitespace technologies ...
 
#21 ·
I agree. IC has no plan because it does whatever the FCC does about 2-3 years later. If the FCC claws back more channels for data services, they will want those Canadian channels shut down within 200 miles of the Canada/US border. Since that's where 90% of Canadians live, it's a de facto claw back in Canada as well.
 
#23 ·
The FCC can want want it wants, but he current agreement protects the stations up to channel 51. Unless there is something in it for the Canadian Government, don't assume IC will go along with the FCC. Protecting 700 MHz band for Canadian interests is probably what the channel 51 issue is about.
 
#24 ·
The moratorium is a sign of the times and future trends. That is, giving personal communications priority over conventional TV. Canadians and Americans want mobile data. Big communications companies want to provide it. Governments make $billions from auctioning clawed back bandwidth. Besides, using contiguous packet networks for data is more efficient than using fixed broadcast frequencies for sparsely spaced TV stations. We should be doing what the UK is doing which is using centralized repeaters with densely packed TV stations to make TV broadcasting more space efficient. With ATSC, stations can be synchronized to reduce co-channel effects and pack the TV band into a smaller space. With today's technology, here is no reason why several station/network repeaters should be using more than one frequency allocation.
 
#26 ·
DTS can't be any worse than having dozens of repeaters on co-channels or adjacent channels to other, totally unrelated stations. That's the situation in Southern Ontario. Here, we have many overlapping network stations which interfere with other overlapping network stations. Even local stations are spread across the entire dial and geographical map. OTA reception is a nightmare and getting worse every year. IC has allowed that with a lot of idiotic channel allocations based on outdated science. The networks and CRTC have thrown a lot of bad business decisions and bureaucratic blunders to make it even worse. It's no wonder most Canadians just give up and pay outrageous prices for TV delivery.
 
#27 ·
why should anyone do anything like the UK? The UK is the UK.
The Geography of the entire UK is roughly twice the size of the state of Pennsylvania. So there isn't really much to cover.
Suspect it would be next to impossible for any government controlled entity to pull something like that off in a country the size of Canada or the US.
 
#28 ·
I agree with majortom. The UK has a much greater population density, so just because it works for them doesn't mean it will work for us.

As for the idea of putting transmitters on all cell phone towers, that would be extremely expensive in both up up front equipment purchases and maintenance. Replacing the one central transmitter with three or maybe four lower powered transmitters might be feasible, but you would then loose rural reception.

A strategy to use low powered UHF transmitters in urban areas and high powered VHF transmitters in rural areas (likely using multicast services) would be necessary, but that would require redesigning the entire band plan from the ground up, which would be a costly exercise for both the government and the stations.
 
#29 ·
It has essentially already been done in the GTA. All transmitters are on a central tower. Even more transmitters would be placed there except for the fact that archaic CTRC regulations prevent it. I am proposing that similar things be done in other cities. That is place all transmitters on a central tower to serve the city and region. It would not only save costs for broadcasters but also make it much easier for consumers since only a single antenna pointed at the closest tower would be required. Channel allocations could be modified in the longer term but that's going to happen anyway as more channels are clawed back and sold to communications companies. Population density and geography have nothing to do with it. If anything, the current system in Canada is counterproductive since it prevents the optimal placement of transmitters in the densest populated locations.

A strategy to use low powered UHF transmitters in urban areas and high powered VHF transmitters in rural areas
If you knew anything about ATSC you would know that high powered VHF stations are impractical due to atmospheric propagation in certain weather conditions. The best use for VHF is low powered local stations. Currently, IC is allocating VHF frequencies for use as low powered regional station, which is ridiculously impractical. (Many US stations have abandoned VHF-lo and obtained higher VHF-hi power permits for this very reason.) UHF is much more practical for high powered regional stations.
 
#30 ·
It has essentially already been done in the GTA. All transmitters are on a central tower.
The argument is against using one centralized tower, but using several/many distributed towers instead.

If you knew anything about ATSC you would know that high powered VHF stations are impractical due to atmospheric propagation in certain weather conditions. The best use for VHF is low powered local stations.
But VHF (especially VHF-LO) is impractical for low powered stations since the noise floor is higher (and fluctuates more), so you need a stronger signal to receive an error free transmission. This is why so many people are having problems with VHF. It is especially apparent in both London and Ottawa where people are having troubles receiving a weak channel 6.

The problem of atmospheric propagation can be resolved by increasing the distance between transmitters on the same channel. My suggestion was to give each region one VHF channel to be shared by all stations to allow this increased spacing.
 
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