Canadian TV, Computing and Home Theatre Forums banner

1 - 20 of 37 Posts

·
Super Moderator
Joined
·
5,074 Posts
We're not losing VHF low. Most stations are moving to higher channel assignments to avoid interference issues common on VHF low. Some stations will still utilize this spectrum, however. And yes, the 700MHz band, comprising channels 52-69, will be auctioned off.

The same thing happened back in the 80's, when the 800MHz band was taken away from broadcasting.
 

·
Registered
Joined
·
8,299 Posts
How is it "stealing"? The government and ITU often update spectrum allocations, as needs change. The original 850 MHz cell phone band was created out of UHF channels 70-83. Back when TV was first introduced, those low channels were valuable, due to better propogation at a time when there were few stations and also equipment costs. However, now there's a lot more interference in that part of the spectrum and digital TV is more sensitive to that interference.
 

·
Registered
Joined
·
7,131 Posts
IMHO, they should reassign VHF-lo as well. It's not suitable for ATSC. Most US broadcasters know that but deadbeat Global wants to keep using it at ridiculously low signal levels. The band might be good for low power community stations but that's about it. There has been talk of using channel 6 for digital FM in the US. Not sure who would want channels 2-5. It's practically useless for AM (aka NTSC) signals due to interference from tropo and nearby electronics.
 

·
Registered
Joined
·
3,262 Posts
Tele-Inter Rives' CHAU-DT wants to use channel 5 for their Carleton station in a hilly region of the Gaspe. They need the range to fed their retransmitters that use OTA pickup.
But they're asking for 9kW (and would prefer 17 kW.)
 

·
Registered
Joined
·
3,396 Posts
Due to severe backlog of unfulfilled FM channel requests, both Ch6 and Ch5 are being proposed
for an expanded FM Band (no real action is evident at this time).
BTW: There is a 4 MHz "gap" between Ch4 and Ch5...

Ch2-4 are reportedly not suitable for mobile devices due to extremely inefficient antenna.

And in the US, the low power TV stations did NOT rush to take over the vacated Lo-VHF allocations,
even though it would greatly lower their monthly power bill.....
 

·
Super Moderator
Joined
·
5,074 Posts
Because it moves available frequencies away from free OTA services into billable services like cell phones.
I don't like the idea of removing spectrum from broadcaster use, but I do understand and support the need for efficient spectrum management. This is why we have DTV: it allows for greater spectral efficiency through multiplexing channels, reduced adjacent channel interference, etc.

The analog radio bands should similarly be forced into digital conversion to promote efficiency there as well.
 

·
Registered
Joined
·
8,299 Posts
^^^^
I wonder how many still listed to the shortwave bands. Bouncing off the ionospere is not kind to digital signals.
 

·
Super Moderator
Joined
·
5,074 Posts
I was more referring to the conventional FM/AM bands. I would certainly agree that shortwave radio would have difficulty with digital signals.
 

·
Registered
Joined
·
3,396 Posts
Adaptive Equalization of a QAM signal described in fol. Canadian Research Center (CRC) Report
"Beyond 9600 bps at HF" (in a 3 kHz voice channel via Ground-wave and/or Ionospheric path):
http://ftp.rta.nato.int/public/PubFullText/RTO/MP/RTO-MP-026/$MP-026-34.PDF
 

·
Registered
Joined
·
9 Posts
It would have been better if 2-6 had been taken away. However, the FCC wants to remove even more UHF channels, possibly all of those above 30 to make way for the National Broadband Plan. They have made sweeping statements that VHF just needs to be "fixed." That's not very easy at all in reality, unless all impulse noise sources are magically removed, along with e-skip, etc.

Upper VHF (7-13) has been enough of a problem and significant power increases have already occurred or been requested in many areas. However, I don't know how much power will make Low-VHF viable for DTV. Certainly, low powered, community stations would only move there in urban areas if they were in a hurry to disappear.

I would much rather see 5 & 6 be turned over to radio. The FM radio (88-108) spectrum is incredibly crowded. In some spots I can clearly hear a San Diego or an Ventura (Northwest of LA) station on the same frequency if I move the car just a few feet! ...there's San Diego, there's Ventura, there's San Diego, etc...

Shortwave radio has a digital mode that's taking hold, but in other parts of the world, known as DRM, Digital Radio Mondiale.

http://www.drm.org/

It isn't much use for high bit-rate applications, such as TV, however.
 

·
Registered
Joined
·
561 Posts
Discussion Starter #13
Sounds like those higher frequencies, 52 thru 69 (or even 83) would have been very useful for digital TV.

Once auctioned off, I have to assume they won't be available in the future for free OTA broadcasts. The OTA digital TV spectrum might not look that populated at the moment, but that might be different in the future. I have to conclude that actioning them off indirectly assists the cable company, the "middle man". I don't like it.
 

·
Super Moderator
Joined
·
5,074 Posts
In the future, better compression and other technologies will compensate for lost spectrum.

The biggest benefactor of spectrum auctions is the government; to the tune of billions of dollars per auction. The reduction in broadcast spectrum hasn't impacted channel startups yet to my knowledge.
 

·
Registered
Joined
·
9 Posts
Yes, 52-69 were quite useful for DTV. We had quite a few back in the day before the transition. Though KABC/53 wasn't that great, a better antenna setup would have fixed that problem. I miss the days where all we needed to worry about in the LA area was UHF for DTV.

Not counting analog stations, we had the following on 52-69 in the LA area, prior to the transition:

KRCA 68
KCOP 66
KTTV 65
KSCI 61
KCBS 60
KCET 59
KABC 53

All had to move. KCBS had a great signal on 60, the best I could receive. To my knowledge, it was also the only full power DTV station that ever existed on 60 (at least in the US).

Now, we are stuck battling with VHF, with more VHF stations likely to follow.
 

·
Registered
Joined
·
9 Posts
The problem with better compression techniques, such as MPEG-4 Pt 10/AVC/h.264 is that another transition will be needed.

However, lacking channels to do this, we would need to simulcast sub-channels on the same physical channel. This is already done extensively in the US, but with mobile DTV looking for bandwidth and with possible HD channel sharing down the road (suggested by the FCC), it will be difficult.
 

·
Registered
Joined
·
561 Posts
Discussion Starter #17
In the future, better compression and other technologies will compensate for lost spectrum.
Disagree, this is a question of proportion. The "better technologies" argument applies to all users of the spectrum & is therefore not valid when reassigning portions of it.

The biggest benefactor of spectrum auctions is the government; to the tune of billions of dollars per auction. The reduction in broadcast spectrum hasn't impacted channel startups yet to my knowledge.
Yes, not YET. The future lies before us and I'm assuming that spectrum will be virtually impossible to get BACK once sold. :mad:
 

·
Super Moderator
Joined
·
5,074 Posts
Disagree, this is a question of proportion. The "better technologies" argument applies to all users of the spectrum & is therefore not valid when reassigning portions of it.
Well, different applications have different requirements. With broadband wireless data, the goal is to get as many users as possible in a quantity of spectrum, while providing as much throughput as possible--in a two-way transmission stream.

With broadcast TV, your data stream is generally fixed, with a one-way transmission. It's comparing apples to oranges.

Yes, not YET. The future lies before us and I'm assuming that spectrum will be virtually impossible to get BACK once sold. :mad:
Under the current regulatory system, there's no incentive to launch a conventional station. The revenue stream for conventional stations is limited to advertising. Whereas with class 2 specialty stations, revenue is FFC and advertising. Further, with the lack of transmitters, the operating costs for specialty stations are lower. And the programming limitations placed on conventional broadcasters are far more strict.

In other words, I don't see any future demand for OTA spectrum from new conventional players, as the potential revenue isn't there. In fact, I see the opposite, as evidenced by SUN TV's recent decision to change their format to all-news specialty--abandoning the conventional TV model.

Future growth, similar to what we've seen stateside, appears to be limited to secondary networks that buy into sub-channels (i.e. "Cool TV", RTV, etc). And that hasn't necessitated additional channel use.
 

·
Registered
Joined
·
7,131 Posts
And in the US, the low power TV stations did NOT rush to take over the vacated Lo-VHF allocations, even though it would greatly lower their monthly power bill.....
Not surprising at all. It seems that antenna makers are abandoning VHF-lo as well, so how are those low power VHF-lo channels going to be received? I certainly don't want to put up a VHF-lo monster on my chimney either. I was looking at Britain's system the other day. It's all UHF with channels clustered on nearby channels in a single, regional location to simplify both broadcasting and receiving equipment. Maybe the situation is a little more complicated here but it sure would be nice to have all the local channels on UHF and in one direction, instead of scattered across 3 frequency bands and half a dozen directions. :confused:
 

·
Super Moderator
Joined
·
5,074 Posts
The problem with better compression techniques, such as MPEG-4 Pt 10/AVC/h.264 is that another transition will be needed.
I don't see this as a problem for one important reason: Consumers won't get the same life expectancy out of flat-screen TV's as they've experienced with CRT's. It will be far easier to incorporate MPEG4/conventional ATSC hybrid tuners into near-future devices, much like we have NTSC/ATSC hybrids now. Then the transition in the future with have minimal impact on consumers.
 
1 - 20 of 37 Posts
Top