Industry Canada puts moratorium on the use of television channel 51
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.
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????
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...
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.
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.
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.
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.
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.
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.
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.