L.A. TV Stations Free Up Some Spectrum For Wireless Broadband

Re:Of course they don't need the full spectrum by Impy+the+Impiuos+Imp · 2014-09-12 01:58 · Score: 1

Apparently you and I lived through completely diffent 1970s.

The only thing superior about analog TV was figiting with the horizontal hold to un-twist scrambled naughty broadcast signals at 1 in the morning.

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Re:Of course they don't need the full spectrum by i+kan+reed · 2014-09-12 02:02 · Score: 1

Yeah, going to echo the sentiments of the poster below, and suggest you don't remember analogue TV. Every bit of noise meant a visual artifact on the screen(or audio). Whereas digital can use an ECC to fix erroneous data.

The big problem is there is a threshold of quality for which a signal simply doesn't work at all. Which means these are the stations that had a constant unwanted background buzz and flickering static for you before.

Seconded! by mmell · 2014-09-12 02:07 · Score: 2

Analog gets a little twitchy, you see snow (or ghosts). Sound has a little static to it. Your brain actually does a fantastic job of filtering these things out (like most people, you see and hear exactly what you want to see and hear).

Digital gets a little twitchy, you see a still frame (or nothing). Sound becomes silent. It's hard for your brain to actually filter out a blank screen and no audio.

Re:Seconded! by i+kan+reed · 2014-09-12 02:14 · Score: 1

Yeah, and I'm saying that those issues kick in under much more extreme conditions than analogue ones.
Re:Seconded! by jones_supa · 2014-09-12 02:25 · Score: 1

Digital gets a little twitchy, you see a still frame (or nothing). Sound becomes silent. It's hard for your brain to actually filter out a blank screen and no audio.
That's just the extreme tipping point. Before reaching that point you can pick up a very crusty signal and still enjoy a perfect picture and audio while the error correction is working its ass off behind the scenes.
With analogue signal as bad, you might already be losing color information, and luxuries like NICAM sound are a distant dream.
Re:Seconded! by mmell · 2014-09-12 02:43 · Score: 1

At the end of the day, all I know is that stations which once were viewable (some even perfect) under analog are no longer viewable under digital. Wrap all the sophistry you want around your arguments - viewable beats not viewable any day, and I've discovered that many previously viewable channels are no longer available to me as OTA. I need to pay for 'em now via the cable and satellite companies. I can't just hand a rabbit ears on the back of my set or go up on my roof and mount a VHF/UHF antenna.
Re:Seconded! by jones_supa · 2014-09-12 02:57 · Score: 1

I have to admit that's a fair argument... :)
Re:Seconded! by petermgreen · 2014-09-12 03:52 · Score: 2

The problem with that theory is what is known of as "impulse interference". When some large and sudden electrical event (distant lightening strikes, switching of large loads, that sort of thing) happens it can create electromagnetic radiation that is very limited in the time domain but very widespread in the frequency domain.
With an analog transmission you get a very brief flicker but stuff almost immediately returns to normal. With compressed and error-corrected digital transmissions either nothing happens at all or the error correction is overwhelmed and the system loses sync. Once it loses sync it takes substantial time for it to get back into sync during which you typically get a frozen picture and no sound.

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Re:Seconded! by wagnerrp · 2014-09-12 07:39 · Score: 1

At the end of the day, all I know is that stations which once were viewable (some even perfect) under analog are no longer viewable under digital.
That sounds like other changes were made at the same time, independent of the digital transition. Their new transmitters are cheap shit. They dropped to a lower transmit power. They moved to a different antenna or frequency that results in increased interference.
Re:Seconded! by iroll · 2014-09-12 09:56 · Score: 1

Why can't you just go up on your roof and mount a VHF/UHF antenna?

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Re:Of course they don't need the full spectrum by afidel · 2014-09-12 02:14 · Score: 2

The problem is that a 6MHz channel only allows ~18Mbps of usable bandwidth using 8VSB (current ATSC standard OTA encoding) which isn't a lot if you're using MPEG2 for 1080i/720p @30fps, cutting it down to ~9Mbps means you're getting worse than DVD bandwidth for what's supposed to be an HD signal.

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Re:Of course they don't need the full spectrum by olsmeister · 2014-09-12 02:15 · Score: 2

They dropped the transmit power when they switched to digital. Theoretically, this was OK because digital receivers can obtain a usable signal from a much lower input power. However in reality, the effective footprint of OTA channels was definitely reduced. During the transition the maximum output power was reduced from 100kW to 45kW, even though digital transmission is only 30% more efficient.

Not in my personal experience. by mmell · 2014-09-12 02:20 · Score: 1

Stations which I used to consider viewable (even some which came in at 0 - -10dB of gain, which is perfect for analog) have disappeared outright, or become modern examples of "flickervision" under digital. Don't fool yourself - the broadcast networks would love to see everyone get their signals from cable or via an encrypted stream from satellite. Instead of the fluctuating income stream bounded by ratings and advertiser whims, they can rely on CableCo for a guaranteed, predictable, reliable revenue stream.

Sharing channel == worse picture quality by sunderland56 · 2014-09-12 02:22 · Score: 1, Insightful

So two stations that were previously using 6 MHz bandwidth each, will now share one channel, presumably using 3 MHz each.... and so each will have a 50% drop in picture quality. How is this a good thing for the consumer?

Re:Sharing channel == worse picture quality by mmell · 2014-09-12 02:35 · Score: 1

An incentive to buy cable or satellite access?
*ducks*
Re:Sharing channel == worse picture quality by crow · 2014-09-12 02:56 · Score: 2

Possibly, but more likely they're dropping their subchannels that were ignored by everyone anyway.
Most broadcasters use their physical channel for one HD logical channel and several SD streams. For example, 4.1 might be HD CBS, 4.2 might be the same thing in SD, and 4.3 might be continuous weather. If they drop the SD channels, they can probably fit in both HD channels with little degradation.
Re:Sharing channel == worse picture quality by Charliemopps · 2014-09-12 02:58 · Score: 1

So two stations that were previously using 6 MHz bandwidth each, will now share one channel, presumably using 3 MHz each.... and so each will have a 50% drop in picture quality. How is this a good thing for the consumer?
You have no idea how "Digital" works do you?
Re:Sharing channel == worse picture quality by Anonymous Coward · 2014-09-12 03:02 · Score: 1

That is not the case. A single 6MHz band can carry multiple "subchannels", practically up to about 5. Most broadcasters are wasting most of their bandwidth, since few transmit more than two subchannels (Ion and PBS being major exceptions). Both of these stations can put a Hi-Def subchannel into that stream, with no problems or loss of quality.
Re:Sharing channel == worse picture quality by davidwr · 2014-09-12 04:26 · Score: 1

So two stations that were previously using 6 MHz bandwidth each, will now share one channel, presumably using 3 MHz each.... and so each will have a 50% drop in picture quality. How is this a good thing for the consumer?
You have no idea how "Digital" works do you?
If by "quality" the original poster meant "maximum picture quality" i.e. the combination of resolution and ability to change the image over time, he is correct. If by "quality" he meant things like noise/static, then for practical purposes you are correct.
A 6MHz channel can support 1 HD channel plus some leftover room, a 50/50 split of that channel cannot.

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Re:Sharing channel == worse picture quality by Ken_g6 · 2014-09-12 05:08 · Score: 1

I don't have cable or satellite, but I heard their picture quality is way worse than broadcast usually has been. This could just be evening the score.

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Re:Sharing channel == worse picture quality by evilviper · 2014-09-12 05:14 · Score: 1

So two stations that were previously using 6 MHz bandwidth each, will now share one channel, presumably using 3 MHz each.... and so each will have a 50% drop in picture quality. How is this a good thing for the consumer?
Answer: Because NOTHING you've said has a shred of truth. You might try looking-up KCET and KLCS before ignorantly spouting off next time...
KLCS has been operating on a waiver... They've never been broadcasting any HD channels, but just 4 SD channels. KCET has one HD 720p channel, and 3 SD subs. The two can pretty easily fit in the 19Mbps bandwidth of a single 6MHz carrier, without degrading quality at all. In addition, both could stand to drop some of those sub-channels...
KCET's NHK channel largely duplicates KSCI's carriage of several hours of NHK programming per day, as well as both KCET and KLCS carrying a half hour segments of NHK on their main channels, several times a day. Incidentally, KSCI has been operating with 9-10 SD subchannels in their single 6MHz channel for years, now.
Answer #2: PBS in the greater Los Angeles area is a complete fucking mess.
Before KCET dropped their PBS affiliation (an idiotic move, but that's another topic), they were just one of 5 PBS stations available in the greater LA area: KCET, KLCS, KOCE, KVCR, KPBS (and likely others). Now they're down to a mere 4, which is still frankly 2 or 3 too many. All of which are broadcasting almost the same content as each other, often at or near each others' time-slots. Each covers their own smaller footprint, with their own smaller niche, getting a fraction of the public donations during their pledge drives. Whereas one single PBS broadcaster in could cover a larger area, get a bigger chunk of viewers, get a bigger chunk of the donations, and improve their programming, accordingly.
KCET should just up and die, already. They dropped their PBS affiliation in a dispute over money, complaining they were paying out half their income to get PBS programming. Since then, their income has dropped by far more than half, because they no longer have any content most anyone wants to watch. They're only delaying the inevitable by selling off their assets; first their large and empty TV studio, and now their transmitter.
It's kind-of a good move for KLCS OTA TV viewers in SoCal, because KCET had invested in building several digital repeaters, to provide a very strong signal in areas where it is difficult or expensive to get Los Angeles area broadcasts. A sadly worthless move once they dropped their PBS affiliation and nobody watched their channel anymore, but getting KLCS on there would deliver PBS content again, and get some use out of it.
https://en.wikipedia.org/wiki/...
The FCC's "repacking" is a dammed cluster-fuck, screwing over OTA viewers (whose numbers are currently RISING after the digital transition made OTA far more viable). By reducing viewing options, and/or pushing broadcasters into less viable channels (eg. VHF-lo) where their broadcast footprint will be reduced, they're starting to destroy the system they've slowly and painfully built-up over the past 75 years. This just for the benefit of cell-phone companies, who would rather throw more money at buying-up the public's available spectrum (at very cheap, fire-sale prices), rather than investing in picocell sites with smaller horizons and much higher frequency reuse. But the one small advantage it offers is the chance for sick and failing TV broadcasters to cash-out in a cash-positive way.
https://en.wikipedia.org/wiki/...

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Re:Sharing channel == worse picture quality by kb7oeb · 2014-09-12 06:14 · Score: 1

So two stations that were previously using 6 MHz bandwidth each, will now share one channel, presumably using 3 MHz each.... and so each will have a 50% drop in picture quality. How is this a good thing for the consumer?
They are sharing 19MB data stream, it means dropping PQ or Sub channels or both
Re:Sharing channel == worse picture quality by Phreakiture · 2014-09-12 07:00 · Score: 1

I have heard that two 720p channels can coexist on one carrier. I haven't heard of anyone doing this with 1080i or 1080p, and I don't know if the 720p channels were running 30 or 60 FPS.

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Re:Sharing channel == worse picture quality by bughunter · 2014-09-12 07:10 · Score: 1

Wish I had a mod point for you today.
I'm very unhappy with the state of PBS in Los Angeles.
For the second biggest TV market in the US, it has a miserable selection of mediocre PBS stations, and very little original content (unlike say WGBH or KQED) but it seems like KOCE is slowly stepping up its game...

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Re:Sharing channel == worse picture quality by wagnerrp · 2014-09-12 08:02 · Score: 1

Channels don't exist on a carrier. The data stream exists on the carrier, the (MPEG2) transport stream is encoded in the data stream, and as many audio and video streams of whatever resolution you want are multiplexed into that transport stream. Only practicality limits you to two 720p60 MPEG2 video streams in a single 6MHz 8VSB band, as the compression levels needed to push further down than that on typical content starts to become very noticeable.
Re:Sharing channel == worse picture quality by wagnerrp · 2014-09-12 08:05 · Score: 1

No. Charliemopps was referring to the fact that you do not subdivide your spectrum. Subchannels are separated logically, not physically. Two video streams on a 6MHz channel is two video streams on a single 6MHz channel, not two video streams each with their own 3MHz channel.
Re:Sharing channel == worse picture quality by omnichad · 2014-09-12 08:11 · Score: 1

Of course its' worse. The cable companies get their feed from an antenna. So they recompress that rather than the original source.
Re:Sharing channel == worse picture quality by omnichad · 2014-09-12 08:12 · Score: 1

Continuous weather is low-motion, low-bandwidth- and usually SD. The main subchannel still has plenty of bandwidth left in that case.
Are stations really still airing SD on a subchannel?
Re:Sharing channel == worse picture quality by TheSync · 2014-09-12 08:40 · Score: 1

I have heard that two 720p channels can coexist on one carrier.
Not two "good quality" 720p channels! MPEG-2 encoder technology (of the highest quality pro encoders) continues to get better, but we're not quite able to fit two good 720p's into 19 Mbps. Give it a year or two.
Of course you can jam in as many video channels as you want if you don't mind it looking like crap in high-motion scenes (like sports for instance).
Re:Sharing channel == worse picture quality by antdude · 2014-09-12 15:35 · Score: 1

I care not about these two stations. They're not good as the old days like in the (19)80s. I used to watch Bob Ross's paintings, This Old House, Sesame Street, Nature, NOVA, National Geographic, Wild America, 3-2-1 Contact, Reading Rainbow, Square One Television (Mathnet!), The Voyage of the Mimi, etc. These days, pretty much NOTHING! :(
Does anyone remember the very old colored animal shows (filmed in 1970s?)? IIRC, each episode was like 30 minutes, different topics, and the ending credits showed a jeep driving at a distance in a sunset driving?

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Re:Sharing channel == worse picture quality by evilviper · 2014-09-13 04:53 · Score: 1

I certainly don't need the mod points, but it's damn sad to see the ass-backwards moderation on this story.
This factually incorrect nonsense is +5:
* http://slashdot.org/comments.p...
While my correction actually got modded down:
* http://slashdot.org/comments.p...
Similarly with this thread, I'm clearly the only one who has provided information specific to the situation, and my comments get ignored, while generalized rants with terrible info are +5.
It's a crushing disappointment to see just what /. has turned into... I can only hope SoylentNews does better.

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Re:Sharing channel == worse picture quality by evilviper · 2014-09-13 05:10 · Score: 1

Sadly, even if we move to picocells, the antennas will still need to be "visible" and will still have some "size" to them due to the frequencies they need to handle.
Actually, wavelength at 800Mhz is only about 1ft (~30cm), so that's practical to hide. Hell, you could disguise it as a chimney or some other roof penetration.
My plan would be to mount them on telephone poles wherever available. There, they could just use business-class cable/DSL/FIOS service as the backhaul. Maybe that possibility would encourage Verizon to expand their FIOS deployment, since the big money is in cellular. AT&T's U-Verse fiber network could support it, too. Sprint/T-Mobile would be at a disadvantage, but maybe deals with local cable companies would help both sides compete. After all, where you need several picocells is right where there are already large populations, and already have wired options installed.
With that plan, cellular data could actually be both faster and cheaper than wired internet access.

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Re:Sharing channel == worse picture quality by bughunter · 2014-09-13 13:51 · Score: 1

Indeed. Slashdot is a nebulous ghost of what it once was. The insightful and informative community seems to have departed for elsewhere, leaving us with trolls, juveniles and politically motivated archive-oriented moderators.

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I can see the fnords!
Re:Sharing channel == worse picture quality by Phreakiture · 2014-09-18 03:20 · Score: 1

Channels don't exist on a carrier.

Unhelpful pedantics. My point, as you correctly gathered, os one of there being or not/being sufficient bandwidth to do the job.

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They also use considerably higher frequencies. by mmell · 2014-09-12 02:39 · Score: 4, Interesting

VHF frequencies tended to flow around obstructions. UHF frequencies tended to be more "line of sight". Modern digital television is on even higher frequencies. Crunch the numbers - this means less coverage by FREE broadcast mechanisms and more incentive for consumers to pay for cable or satellite reception. "Broadcast" companies get a reliable revenue stream, cable and satellite companies get a de facto monopoly and the government gets another choke point on communication. Everyone wins!

Well, everyone except Joe Sixpack; but he's just an ignorant dolt anyhow (an insensitive clod?).

Re:They also use considerably higher frequencies. by kilodelta · 2014-09-12 04:45 · Score: 1

Well of course and let me tell you that both VHF and UHF suffer the line of sight problem.

But you're right - I've pulled in 20 or 30 stations with a piece of 8 to 10 foot long wire from my first floor place. Just insert it into the center pin where the cable F connector would normally go.

And those of us in Urban environments tend to get better service that way anyhow.

Re:Of course they don't need the full spectrum by neo-mkrey · 2014-09-12 02:40 · Score: 1

You forgot to end with, "Get off my lawn!"

Digital would be less "twitchy", but... by Ken_g6 · 2014-09-12 02:44 · Score: 1

Digital becoming twitchy isn't just because of transitioning to digital. It's also because they lowered the transmitter power.

The maximum power for DTV broadcast classes is also substantially lower; one-fifth of the legal limits for the former full-power analog services. This is because there are only eight different states in which an 8VSB signal can be in at any one moment; thus, like all digital transmissions, very little signal is required at the receiver in order to decode it.

So if you were watching an analog signal of the same power, you'd have a hard time making it out too.

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Re:Digital would be less "twitchy", but... by Trip+Ericson · 2014-09-12 03:16 · Score: 1

Analog power was measured as peak power while digital power is measured as average power. If you measured analog power in average, that 100 kW would become about 25 kW (less than the 45 kW ceiling). A similar difference arises between 316 kW becoming about 80 kW (less than the 160 kW ceiling). On UHF, the power difference is 5000 kW for analog versus about 1250 kW for digital, slightly more than the 1000 kW ceiling, but only by about 1 dB.
On top of that, about 50 dB SNR was needed for a clear picture with an analog signal, while a digital signal requires only 16 dB for a perfect decode. So the difference in required SNR is more than 30 dB, but the power change, even if it actually was 5000 kW to 1000 kW, is only 7 dB.

Re:Of course they don't need the full spectrum by Trip+Ericson · 2014-09-12 03:15 · Score: 3, Informative

Analog power was measured as peak power while digital power is measured as average power. If you measured analog power in RMS, that 100 kW would become about 25 kW (less than the 45 kW ceiling). A similar difference arises between 316 kW becoming about 80 kW (less than the 160 kW ceiling). On UHF, the power difference is 5000 kW for analog versus about 1250 kW for digital, slightly more than the 1000 kW ceiling, but only by about 1 dB.

On top of that, about 50 dB SNR was needed for a clear picture with an analog signal, while a digital signal requires only 16 dB for a perfect decode. So the difference in required SNR is more than 30 dB, but the power change, even if it actually was 5000 kW to 1000 kW, is only 7 dB.

Re:Of course they don't need the full spectrum by Trip+Ericson · 2014-09-12 03:20 · Score: 1

I meant "average" and not "RMS" in my second sentence. Wish I could edit...

Modern UHF vs. classical UHF by davidwr · 2014-09-12 03:22 · Score: 3, Informative

Modern digital television is on even higher frequencies.[than analog UHF]

Not true. Digital television frequencies are basically the same as the analog ones, with some channels either no longer used or no longer used except under special circumstances (e.g. grandfathered stations, low-power stations, etc.).

In practice, most US digital TV stations are UHF stations between channels 14 and 69.

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Re:Modern UHF vs. classical UHF by mmell · 2014-09-12 04:07 · Score: 1

You're right, I misread the spec. However, they're still tending to favor those areas of bandwidth that are notably less efficient. While I don't have evidence to support this contention, I perceive that it is an intentional act designed to minimize OTA access to broadcast television, a cynical act designed to encourage or even force viewers to subscribe to cable or satellite services.

Re:Of course they don't need the full spectrum by petermgreen · 2014-09-12 03:37 · Score: 1

That's the frustrating thing about digital broadcasts. With analog you have a gradual variation in quality and can tweak your antenna to get it as good as you can. With digital if your reception is on the edge you get a perfect picture/sound most of the time but occasionally (how occasional depends on how marginal the reception is and what interference sources you have arround) multi-second breakups when impulse interference causes the error correction to fail and the whole system has to re-sync.

A perfect picture most of the time with periodic multi-second breakups is much worse than a fuzzy picture with periodic interference flashes.

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Re:Of course they don't need the full spectrum by k6mfw · 2014-09-12 05:38 · Score: 1

I'm somewhat confused. Each ATSC channel is a fixed 6 MHz wide spectrum. They can either do one HD channel or four SD channels (I think but I cannot find solid technical info on TV broadcast except very general info that is aggregates of what everyone else posted, or very esoteric technical specific). I can get MPEG2 is high bandwidth and not that great compared to H264 but MPEG2 continues on because that's the way it is (like DVDs).

I was talking with someone who gave additional reason to cut cord from Comcast is HD from OTA is far superior than on cable which is highly compressed to transmit all those channels down the coax.

Speaking of technical, it was only recently you can easily find actual frequencies used by TV stations (needed if you are using UHF wireless mics). After the DTV transition, I could not find actual frequencies used which drove me nuts because those that say it is same as NTSC are wrong (well yes and no, digital channel is same freq as NTSC channel, but stations go by virtual channel which many are different). Get the freq here,
http://licensing.fcc.gov/cdbs/... put CA for state to show all broadcast TV stations in Calif.

for this diatribe, here's the data of these two stations from FCC site (freq from old school NTSC channel):
both stations are Full(DT) in Los Angeles Call Sign KLCS
Virtual Ch 58
Digital Ch 41 [632-638 MHz]
Licensee LOS ANGELES UNIFIED SCHOOL DISTRICT

Call Sign KCET
Virtual Ch 28
Digital Ch 28 [554-560 MHz]
Licensee KCETLINK

Oh well, for you all RF types (yes, there is a low power NTSC station on analog ch 6),
Call Sign, Virtual Ch, Full/Low Power, Digital Ch, Licensee
KABC-TV 7 Full(DT) 7 ABC HOLDING COMPANY, INC.
KCAL-TV 9 Full(DT) 9 LOS ANGELES TELEVISION STATION KCAL LLC
KCBS-TV 2 Full(DT) 43 CBS BROADCASTING INC.
KCET 28 Full(DT) 28 KCETLINK
KCOP-TV 13 Full(DT) 13 FOX TELEVISION STATIONS, INC.
KEDD-LD - Low (LD) 50 VENTURE TECHNOLOGIES GROUP, LLC
KFLA-LD - Low (LD) 8 ROY WILLIAM MAYHUGH
KHIZ-LD - Low (LD) 2 JEFF CHANG
KHTV-CD - Low (DC) 27 VENTURE TECHNOLOGIES GROUP, LLC
KIIO-LD - Low (LD) 10 BAGRAT SARGSYAN
KLCS 58 Full(DT) 41 LOS ANGELES UNIFIED SCHOOL DISTRICT
KMEX-DT 34 Full(DT) 34 KMEX LICENSE PARTNERSHIP, G.P.
KMRZ-LD - Low (LD) 22 VENTURE TECHNOLOGIES GROUP, LLC
KNBC 4 Full(DT) 36 NBC TELEMUNDO LICENSE LLC
KNET-CD - Low (DC) 25 NRJ TV III CA LICENSE CO., LLC
KNLA-CD - Low (DC) 50 NRJ TV III CA LICENSE CO., LLC
KSFV-CD - Low (DC) 22 VENTURE TECHNOLOGIES GROUP, LLC
KSFV-LP 6 Low (TX) Analog Ch 6 VENTURE TECHNOLOGIES GROUP, LLC
KSMV-LD - Low (LD) 23 KJLA, LLC
KTBV-LD - Low (LD) 12 EICB-TV WEST, LLC
KTLA 5 Full(DT) 31 KTLA, LLC
KTTV 11 Full(DT) 11 FOX TELEVISION STATIONS, INC.
KVHD-LD - Low (LD) 40 NEW YORK SPECTRUM HOLDING COMPANY, LLC
KWHY-TV 22 Full(DT) 42 KWHY-22 BROADCASTING, LLC

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Quality Loss Depends by spleck · 2014-09-12 05:49 · Score: 1

In my area, many of our OTA network stations share a channel (due to financial issues, not to free up spectrum). Fox/ABC, CBS/CW, NBC/myTV.

I think most programs have no issues with 12+ Mbps, which usually leaves room for a SD sub-channel. However, shoving two HD programs into a 6 MHz channel leaves each ~9 Mbps. Sports programs suffer significant blocking and pixelation on fast action and pans. Live shows such as America's Got Talent also block and pixelate. Studio shows fare better.

I believe the problem may vary based on market since, I assume, the broadcasts are re-compressed locally and we're at the mercy of the capability of whatever system my money-starved stations purchased. NBC and CBS are the worst here, and I'm not sure if it's their choice of compression hardware or just that 1080i suffers more than 720p.

So basically on these shared channels, you suffer from limited bandwidth, re-compression artifacts (going form 12-18 Mbps down to 9), and local hardware limitations (poor quality compressor, no pre-processing/single-pass only, etc).

Re:Quality Loss Depends by wagnerrp · 2014-09-12 08:09 · Score: 1

Generally studio shows fare better because they're only 24fps with frame duplication. There's simply much less data to send.

Re:Of course they don't need the full spectrum by spleck · 2014-09-12 05:58 · Score: 1

I was talking with someone who gave additional reason to cut cord from Comcast is HD from OTA is far superior than on cable which is highly compressed to transmit all those channels down the coax.

I long suspected Cox cable re-compressed our local stations, but then found out all the stations are sharing 2 HD stations per transmitter, some with an extra SD subchannel. So even over the air, all my locals are less than 9 Mbps. Cox has the dirty work done for them already, and just sends out the same signal.

Re:Of course they don't need the full spectrum by wagnerrp · 2014-09-12 07:42 · Score: 1

I'm somewhat confused. Each ATSC channel is a fixed 6 MHz wide spectrum. They can either do one HD channel or four SD channels

There's no explicit maximum, or at least none that you could ever reasonably reach. It all comes down to how much you compress the data. You can run dozens of HD channels on a single multiplex if they look like shit, or are primarily static images.

Re:Of course they don't need the full spectrum by wagnerrp · 2014-09-12 07:56 · Score: 1

78s and 45s are still better than digital.

Old 78s and 45s were never better than digital, in any fashion. They added weight and ceremony to listening to music, because of the care needed in using them. They added distortions that people like to call "warmth". Both of these are form, and run in direct violation to their primary function as a storage medium.

Signal strength button by tepples · 2014-09-12 11:02 · Score: 1

With analog you have a gradual variation in quality and can tweak your antenna to get it as good as you can. With digital if your reception is on the edge you get [...] multi-second breakups

Better receivers, such as the box I bought in the coupon era, have a button on the remote that pops up a signal strength meter. I don't know whether that just means raw level of the signal or the actual SNR, but it has helped me aim the antenna to minimize signal dropouts.

Renting by tepples · 2014-09-12 14:01 · Score: 1

Why can't you just go up on your roof and mount a VHF/UHF antenna?

It could be technically the landlord's roof, not mmell's.

Re:Renting by evilviper · 2014-09-13 05:27 · Score: 1

It could be technically the landlord's roof, not mmell's.
As long as mmell doesn't share the roof with other tennants, he has the right to mount an antenna up there.
Law of the land since 1996:
http://www.fcc.gov/guides/over...

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That's not relevant by davidwr · 2014-09-12 16:07 · Score: 1

Two video streams on a 6MHz channel is two video streams on a single 6MHz channel, not two video streams each with their own 3MHz channel.

That's not relevant.

What is relevant is that you can't squeeze blood out of a turnip.

If you are logically splitting the bandwidth with another broadcaster and you are broadcasting a show that uses 50% of the bandwidth, that only leaves 50% for the other broadcaster. If you want to broadcast a show that requires more bandwidth, such as a typical HD (1080p) television show, it can't do it unless the other broadcaster isn't trying to use more than the remaining bandwidth during that time period.

Assuming you can't get the other broadcaster to cooperate, you can't broadcast with the same "quality" (as defined by resolution and frequency-of-scene-changes) as you could if you controlled the entire 6MHz channel.

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Re:That's not relevant by wagnerrp · 2014-09-13 01:38 · Score: 1

Assuming you can't get the other broadcaster to cooperate, you can't broadcast with the same "quality" (as defined by resolution and frequency-of-scene-changes) as you could if you controlled the entire 6MHz channel.
There is only one broadcaster. There is only one MPEG2 transport stream, now containing both programs. They must cooperate, as they are sharing one piece of transmission gear. It's not like a cellular network where two different entities are sharing time slices of a common spectrum. Also, I'm not aware of any broadcaster that uses 1080p.
Re:That's not relevant by davidwr · 2014-09-13 05:03 · Score: 1

I should have said 1080i, not 1080p. My point was, if both television programs (as seen by the viewer) take up so much bandwidth that there is not enough room for the other program to be at "maximum quality," then the other program will not be at "maximum quality" and the earlier editor's claim that channel-sharing (typically) results in a lower maximum-quality show (as displayed on the customer's screen) is true.
Also, of course the two companies must cooperate in a technical sense. I should have clarified that by "cooperate" I meant in a business sense, as in "okay, you want to transmit an HD program from 7-8PM on December 1 and you say that the nature of the program requires that you use minimal compression and you will need at least 15 Mbit/s of the available bandwidth? We already have plans to broadcast a show at 720p during that time slot. We can't both be on at the same time. How about you do your broadcast with some compression from 7-8PM then replay it after midnight with minimal compression when we are off the air?"
If the stations cooperate in this way and the viewer watches both the heavily-compressed and the lightly-compressed version of the 1080i show, there will almost certainly be perceptible differences in quality.
On the other hand, of the stations cannot cooperate, say, because the station that is not doing the 1080i program is airing 720p programming 24x7, then the viewer will be stuck with the lower-quality version.

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Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.

The other KCET by tepples · 2014-09-12 16:38 · Score: 1

Before KCET dropped their PBS affiliation (an idiotic move, but that's another topic)

What are they affiliated with now? Konami Computer Entertainment Tokyo?

Modern UHF vs. classical UHF by donghogiabao · 2014-09-12 17:42 · Score: 1

I agree with this point

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Re:Of course they don't need the full spectrum by evilviper · 2014-09-13 05:23 · Score: 1

Speaking of technical, it was only recently you can easily find actual frequencies used by TV stations (needed if you are using UHF wireless mics). After the DTV transition, I could not find actual frequencies used which drove me nuts because those that say it is same as NTSC are wrong

Umm, tvfool.com has had that info forever.

I linked to the FCC's DTV transition plan in my journal about OTA TV in 2007:

http://slashdot.org/journal/18...

Specifically:
"FCC DTV tentative frequency assigments"

http://hraunfoss.fcc.gov/edocs...

If you're talking about the center frequency, that's a very simple conversion. The Linux DVB package contains two text files listing center frequencies:

us-NTSC-center-frequencies-8VSB
us-ATSC-center-frequencies-8VSB

ATSC eg.:
A 57028615 8VSB
A 63028615 8VSB
A 69028615 8VSB
A 79028615 8VSB
A 85028615 8VSB

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Multi-family units by tepples · 2014-09-13 07:44 · Score: 1

I don't know whether mmell shares a roof, but I read your comment after having just got back from helping move a relative and her children into an apartment where she does share the building with up to 15 other families.

Re:Multi-family units by evilviper · 2014-09-13 11:03 · Score: 1

an apartment where she does share the building with up to 15 other families.
That doesn't preclude installing an antenna, it just reduces your options. Multi-floor apartment balconies and/or windows usually get pretty good TV reception. If previous occupants had DBS dishes mounted, you can stick an antenna on that J-channel. And landlords are usually reasonable. You can always ask for permission to install an antenna, explaining the non-destructive mounting option (chimney straps, non-penetrating root mount, etc.) you'd like to use, and promise it'll be less unsightly than what you'll do if they refuse.

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