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post #1201 of 1223 Old 07-17-2016, 10:20 AM
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NO....the "Cable Headend" refers to the various Cable and Video MANAGEMENT Processors and Mass Storage Arrays, the combined OUTPUT consisting of a very high data rate digital signals that drive each bank of QAM Modulators [one per "Neighborhood Node", multiple QAM Modulators per Circuit Card]. The Combined [54-1002 MHz...or whatever] RF Output is then DIGITIZED and Multiplexed with OTHER Node Signals down each of the Optical Fibers.

A FO Cable Network (each FO Cable consisting of MANY Parallel Fibers) is distributed throughout the Local Area to many Neighborhood Distribution Boxes containing an FO-To-WIDEBAND RF Converter (ALL 158 Channels in ONE Digitized Signal) and a 54-1002 MHz (or 862 MHz or whatever) wideband RF Power Amplifier that drives the LOCAL RF CABLE Network. Most users are within a short walking distance to their "Neighborhood" FO-to-Cable Distribution Box. The RF Cable Network is usually a Daisy Chain of Multi-Port Splitters and/or Directional Coupler Boxes, each driving perhaps 8 to 16 single family homes.

Photo of FO-to-Cable Distribution Box that Georgetown Historical District was NOT happy to see:
http://patch.com/district-columbia/g...photo-12031730

Photo of RF Splitter/Directional Coupler Box:
https://consumerist.com/2008/05/05/c...x-on-your-lawn

Fol. describes some of the HFC Variations:
http://www.olson-technology.com/AppN...c-networks.pdf
It is also now possible for a SINGLE CHIP to generate ALL of up to 128 QAM256 Channels [plus another for DOCSIS 3.0 Bonded Cable Channels], allowing the QAM Modulator to be pushed down to the Neighborhood Distribution Box:
https://www.maximintegrated.com/en/p...f/MAX5880.html

So YMMV, depending on the age of equipment and equipment choice for EACH Local MSO...

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post #1202 of 1223 Old 07-17-2016, 11:01 AM
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Interesting -- pedestals such as the one labeled "RF Splitter/Directional Coupler Box" have been around for decades. They have always been used to house largeer active electronics, such as bridgers and mini-bridgers. Splitters and directional couplers (passive devices) have always been in smaller pedestals that don't have ventilation slots (don't need ventilation for passive devices).

CIAO!

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post #1203 of 1223 Old 07-17-2016, 11:09 AM
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They are making twice the number of cars available. If a car can comfortably seat, say, 200 people, and there are 250 crammed in there, nobody's going to be comfortable and it's going to be an unpleasant ride. If they add another car, then there are 125 people in each car. Yes, there's plenty of room for more passengers to get on (some will get on in one car, some will get on in the other car), but everyone's going to be a whole lot more comfortable regardless of how many more get on.




I can't speak to what you see. I signed up for Comcast HD when it first became available here, which was 7 or 8 years ago, and the picture quality was amazing. My wife actually sat there with her jaw dropped the first time she saw it. I left for DirecTV because Comcast was very slow to add HD channels, and D* had a couple of channels that I wanted. I returned to Comcast a couple of years ago because of a bundling offer that saved me a ton of money. The number of HD channels has increased significantly, and the picture quality is just as excellent as ever.

I never had any complaints about the D* picture quality, either.
Then consider yourself lucky. Maybe Comcast just isn't spending any money to improve things in my area(San Francisco Bay Area). When I first got Comcast HD 7 years ago I had the same response as you and your wife did. Now I might as well just watch the SD channels since there is hardly any difference.

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When you say "Cable Headend," I assume you mean the beginning of the coaxial distribution system, not the actual headend, which can be several miles away.
I was wondering the same thing. The headend for me is ~20 miles away.
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post #1204 of 1223 Old 07-17-2016, 11:31 AM
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Cable Headend is at the beginning of the FIBRE-OPTIC Distribution Network....in San Diego I think that there are only TWO or THREE in the entire County....one for TWC (maybe TWO, since North County used to be Adelphia???) and another for COX.
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post #1205 of 1223 Old 07-17-2016, 11:53 AM
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Originally Posted by holl_ands View Post
Cable Headend is at the beginning of the FIBRE-OPTIC Distribution Network....in San Diego I think that there are only TWO or THREE in the entire County....one for TWC (maybe TWO, since North County used to be Adelphia???) and another for COX.
Earlier you wrote "NEW Cable Headend [located at a Central Cable Plant] includes Cable Modem Management, Cloud-DVR/VOD/PPV Program Management/STORAGE, Video Management for "Real-Time" Video Streams [incl. SDV if ever implemented] and the EXISTING Inventory of Fibre Optic to QAM Modulators (and maybe some Analog Channel Modulators) that are likely located within 1/2-mile of your location." (emphasis added) Which is it, either 1 for the system or 1 likely located within 1/2 mile of your location?

CIAO!

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post #1206 of 1223 Old 07-17-2016, 02:56 PM
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I still don't understand why you have this crazy idea that TiVo has such high overhead. Low volume? Yes, probably because the cost is so damn high. If you charge a ridiculously high cost for something you probably aren't going to sell that many. High overhead? Not really.
They have overhead, and they don't have a high volume to split that out over.

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What would be the point of using Cloud DVR when watching recordings on the box? It doesn't even make sense. Why cause congestion on the network? Sure, it might use IP instead of QAM but I think we can agree that using NO bandwidth is better than using a small amount of bandwidth.
True, but this is Comcast we're talking about. How exactly Cloud DVR works is still unclear, and how it will work in the future is also unclear.

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Since I've been considering switching to DirecTV(since Comcast signal sucks so bad) I've used the box at a few AT&T stores. It really does suck. It is a tiny bit faster but feature wise it's about equal with my old non-X1 Motorola box from Comcast. Menu navigation is very unintuitive, search sucks and the remote is awful. I've said in previous posts that I don't like the TiVo remote(I think you called it a "peanut"?) but even that is excellent compared to the DirecTV remote. The X1 UI, despite being a little sluggish at times(but not enough to really make it a pain to use), is the best I have used.
I can't trust your impressions of things, since you don't recognize TiVo and the Peanut as the best DVR and remote every made. I've had X1 and TiVo next to each other, and the X1 sucks in comparison to TiVo.

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I agree that sending every signal all the time is a dumb idea. Compressing QAM may not directly have an impact on the ability to stream 4K but it does indirectly have an impact since QAM does take up bandwidth on the same pipe that IP uses. Compressing the QAM signals more means more bandwidth that can be given to IP traffic. Pushing fiber deeper into the field does have an impact on picture quality because more fiber means more bandwidth which means less need to compress so much.
Pushing fiber deeper into the field adds more total IP bandwidth over the system by splitting nodes, but it doesn't help for linear QAM bandwidth, since Comcast doesn't use SDV.

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So lets say there is an area of 1,000 homes being serviced by one node capable of 100Gbps total to those 1,000 homes. Now lets say you were to split that node. Now you have two nodes each servicing 500 homes. It seems to be that for the split to be a benefit the total bandwidth for that 1,000 home area would need to increase. If I was previously on a node getting 1/1,000 of 100Gbps and now I'm on a node that is getting 1/500 of 50Gbps how does that make anything better? At some point in the line you'd have to upgrade the infrastructure to that area to supply more bandwidth.

I found this image for example.

https://upload.wikimedia.org/wikibooks/en/e/ea/Inoc.jpg

When you split a node you would have to have more bandwidth going from the head-end to the point of the split(see the middle switch with the 2 fiber nodes coming off of it). The problem is that the head-end doesn't have enough bandwidth to feed all the nodes. And as we both know that head-end is serving both IP and QAM signals. It's still ONE PIPE from the head-end. You can split the node as many times as you want but unless you make that pipe from the head-end "bigger" you aren't going to solve the problem. What my point has been is that the ONE PIPE feeding all those nodes from the head-end just isn't "big" enough especially with QAM still a major part.

If the infrastructure was already good enough to support mass 4K streaming then there would be A LOT of unused bandwidth at this point since very few people are streaming in 4K. If that was the case then the extra bandwidth could be used for typical QAM TV broadcasts requiring less compression of current QAM TV signals resulting in a much better picture. Yes, I get it, QAM is bad and will eventually go away in favor of IP but it isn't the case right now. Especially where I live. If Comcast could provide a less compressed QAM signal I'm pretty sure they would so they wouldn't have to deal with people like me calling up day after day, week after week telling them my picture sucks(I have a supervisor tech coming tomorrow) and threatening to switch to DirecTV. The fact that they aren't doing that makes be believe that they CAN'T do it right now. Even without a very detailed technical understanding of how the specific technology works it just takes some common sense to realize the network is not even close to allowing mass 4K.

If the bandwidth currently exists but isn't even close to hitting capacity for IP services then transfer that bandwidth to where it would actually make a difference.....QAM. Seems pretty simple to me.
Again, you're comparing apples and oranges. I guess they could go backwards and reduce HSI bandwidth for TV picture quality, but bandwidth demand keeps going up and up, 4k or not, and without IP or SDV that has to come from somewhere.

You're way overcomplicating how nodes work. Simple example. On my system, we have 304mbps of bandwidth on each node. I believe that my apartment complex and a condo complex down the road are on the same node. For the sake of the example, assume each has 300 units, 600 total (there are a few random houses too, but we'll just ignore them for simplicity). Right now, 600 customers passed (assume 300 active customers) share 304mbps of bandwidth. If they spilt the node, 150 active customers in one complex would have 304mbps, and 150 active customers in another complex would have 304mbps. Once you're at the node level, there is virtually unlimited bandwidth, as everything is fiber, so it's the literal last mile (in urban areas, it's often the last half-mile or less, even the last few hundred feet in very dense areas) that is shared and limited by the RF spectrum.
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post #1207 of 1223 Old 07-17-2016, 06:10 PM
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Originally Posted by egnlsn View Post
Earlier you wrote "NEW Cable Headend [located at a Central Cable Plant] includes Cable Modem Management, Cloud-DVR/VOD/PPV Program Management/STORAGE, Video Management for "Real-Time" Video Streams [incl. SDV if ever implemented] and the EXISTING Inventory of Fibre Optic to QAM Modulators (and maybe some Analog Channel Modulators) that are likely located within 1/2-mile of your location." (emphasis added) Which is it, either 1 for the system or 1 likely located within 1/2 mile of your location?
I'm not exactly sure WHAT COMCAST implemented in each Location....both are possible.....which is why I revised the post....
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post #1208 of 1223 Old 07-18-2016, 10:07 AM
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I can't trust your impressions of things, since you don't recognize TiVo and the Peanut as the best DVR and remote every made. I've had X1 and TiVo next to each other, and the X1 sucks in comparison to TiVo.
You are speaking as a matter of fact on something that is a matter of opinion. TiVo is better than X1 TO YOU.

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Pushing fiber deeper into the field adds more total IP bandwidth over the system by splitting nodes, but it doesn't help for linear QAM bandwidth, since Comcast doesn't use SDV.
Well something has happened to make the picture quality so poor. Something that wouldn't have been done unless it was necessary. Up until about a year ago Comcast HD looked great. Very sharp/clear picture. Now it is absolutely terrible. The level of compression is ridiculous. All channels are impacted. Some more than others. When the HD feed of FOX doesn't look much different than the SD feed then something is very wrong.

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Again, you're comparing apples and oranges. I guess they could go backwards and reduce HSI bandwidth for TV picture quality, but bandwidth demand keeps going up and up, 4k or not, and without IP or SDV that has to come from somewhere.
If bandwidth is going up and up picture quality shouldn't be going down. You said in a previous comment that Comcast's network is capable of handling mass 4K. If that is the case then there shouldn't be a need to reduce HSI bandwidth for TV picture quality.

Let me put it this way. Let's assume you are correct and Comcast's network can easily handle mass 4K. Right now most people don't have 4K TVs and those that do don't have a very large selection of 4K content for streaming and NO selection for regular broadcast TV. That means very few people are watching anything in 4K which means that the network utilization should be WELL BELOW CAPACITY. That's just deductive reasoning and common sense. Given that network utilization is well below capacity there is no reason for the decrease in cable TV picture quality. The fact that the cable TV picture quality has dropped to abysmal levels over the last 1-1.5 years gives me strong reason to think that your statement that the network could easily handle mass 4K is just not true.


If you are such an expert in Comcast's network then maybe you can tell me why the cable has gotten so damn bad.

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You're way overcomplicating how nodes work. Simple example. On my system, we have 304mbps of bandwidth on each node. I believe that my apartment complex and a condo complex down the road are on the same node. For the sake of the example, assume each has 300 units, 600 total (there are a few random houses too, but we'll just ignore them for simplicity). Right now, 600 customers passed (assume 300 active customers) share 304mbps of bandwidth. If they spilt the node, 150 active customers in one complex would have 304mbps, and 150 active customers in another complex would have 304mbps. Once you're at the node level, there is virtually unlimited bandwidth, as everything is fiber, so it's the literal last mile (in urban areas, it's often the last half-mile or less, even the last few hundred feet in very dense areas) that is shared and limited by the RF spectrum.
That proves what I said earlier. If 300 active users were previously sharing 304Mbps before the split and now, after the split, half the active users(150) have that same 304Mbps that means that the total bandwidth for that 300 active user area as effectively doubled from 304Mbps to 608Mbps. Fiber does not have "virtually unlimited bandwidth". Fiber, like coax, has a peak capacity. At some point you just have to add more fiber.

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post #1209 of 1223 Old 07-18-2016, 11:19 AM
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I'm not exactly sure WHAT COMCAST implemented in each Location....both are possible.....which is why I revised the post....
There is 1 and only 1 headend in a cable TV system, and that is at the beginning of the system. That's where all of the satellite receiving equipment (dishes, receivers, decoders, etc.), local channel receiving equipment, local insertion equipment, combiners, CMTS, modulators (QAM and, if applicable, analog), fiber transmitters, etc. are located. The only things out in the plant are the fiber optic receivers (commonly called "nodes"), amplifiers, directional couplers, splitters, and taps. The page at Olsen Technology to which you linked indicates that as well. Even the High-Density Downstream Cable QAM Modulator and Digital Upconverter to which you linked goes in the headend, not out in the plant.

CIAO!

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post #1210 of 1223 Old 07-18-2016, 11:28 AM
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Cable Headend is at the beginning of the FIBRE-OPTIC Distribution Network....in San Diego I think that there are only TWO or THREE in the entire County....one for TWC (maybe TWO, since North County used to be Adelphia???) and another for COX.
The more likely scenario is that they ran some fiber between the TWC and Adelphia headends, and fed the old Adelphia plant off the TWC headend. It not only makes everything uniform, it also allows them to shut down 1 of the headends, saving a lot of money.

CIAO!

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post #1211 of 1223 Old 07-18-2016, 08:37 PM
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The more likely scenario is that they ran some fiber between the TWC and Adelphia headends, and fed the old Adelphia plant off the TWC headend. It not only makes everything uniform, it also allows them to shut down 1 of the headends, saving a lot of money.
Comcast hasn't figured that one out yet. We still have at least 10 different Comcast systems, and they are all a bit different, and some are rebuilds, and some aren't. It's a complete and total mess out there. At least you'd think that they could harmonize the offerings among them even if they have separate physical headends. All they have closed are some of the stores, meanwhile they are "improving" customer service lol.
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post #1212 of 1223 Old 07-18-2016, 08:50 PM
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You are speaking as a matter of fact on something that is a matter of opinion. TiVo is better than X1 TO YOU.
It's true that it's hard to objectively measure how good a GUI is, but having used both side by side, I know that TiVo is just a better interface. I suppose you could say that you like iGuide better, but few would argue it's better than anything else. X1 is certainly an improvement over iGuide, but it's just not at the level of a real TiVo.

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Well something has happened to make the picture quality so poor. Something that wouldn't have been done unless it was necessary. Up until about a year ago Comcast HD looked great. Very sharp/clear picture. Now it is absolutely terrible. The level of compression is ridiculous. All channels are impacted. Some more than others. When the HD feed of FOX doesn't look much different than the SD feed then something is very wrong.
They've been screwing around with compression for years, and they keep squishing it more and more. It seems to get better, then they figure out how to cram more channels in, and it goes back to where it was, lock and re-load. We went from 2 HDs plus some SDs per QAM to 3HDs to 4HDs, and instead of going to 7 or 8 per QAM with MPEG-4, they decided to lean heavily on statistical multiplexing and cram 10 per QAM, and now we're where we are in MPEG-4 markets where MPEG-4 looks just as bad as the 4 per QAM MPEG-2.

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If bandwidth is going up and up picture quality shouldn't be going down. You said in a previous comment that Comcast's network is capable of handling mass 4K. If that is the case then there shouldn't be a need to reduce HSI bandwidth for TV picture quality.
That comment makes no sense. They have compressed more and more in order to put more bandwidth towards HSI and less towards linear QAM, and the quality has suffered as a result. What you're saying about putting bandwidth back on the QAM side would be moving backwards for the HSI network.

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Let me put it this way. Let's assume you are correct and Comcast's network can easily handle mass 4K. Right now most people don't have 4K TVs and those that do don't have a very large selection of 4K content for streaming and NO selection for regular broadcast TV. That means very few people are watching anything in 4K which means that the network utilization should be WELL BELOW CAPACITY. That's just deductive reasoning and common sense. Given that network utilization is well below capacity there is no reason for the decrease in cable TV picture quality. The fact that the cable TV picture quality has dropped to abysmal levels over the last 1-1.5 years gives me strong reason to think that your statement that the network could easily handle mass 4K is just not true.
4k is not the only thing that's been using more bandwidth in the past 13 years, when we went from one QAM with 1.5mbps service to 8 or 16 QAMs with 150mbps service. Again, you're just mixing the QAM side and the DOCSIS side, and it doesn't work that way. They are basically two totally different things sharing a cable. You've got your whole argument backwards. The TV picture quality has dropped in part BECAUSE they have added so much HSI bandwidth over the past few years, and that's why there is so much capacity on the IP side for 4k.

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If you are such an expert in Comcast's network then maybe you can tell me why the cable has gotten so damn bad.
HELLO! As I've described about five times already, it's because they have been building out their HSI network at the expense of QAM bandwidth without using SDV or IPTV in order to gain bandwidth savings from not having to broadcast everything all the time, even on a smaller node system.

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That proves what I said earlier. If 300 active users were previously sharing 304Mbps before the split and now, after the split, half the active users(150) have that same 304Mbps that means that the total bandwidth for that 300 active user area as effectively doubled from 304Mbps to 608Mbps. Fiber does not have "virtually unlimited bandwidth". Fiber, like coax, has a peak capacity. At some point you just have to add more fiber.
Now you get it! You were *very* confused about it before. The key word on fiber is *virtually*. That means *relative to everything else*, i.e. relative to the bandwidth of the coax cable, and the bandwidth of the connections in the home used to transmit the data. The fiber to the node basically transmits that node's coax just over fiber, but the backbone of the network from the head end upwards can be built with 40gbps fiber, which even when they start pushing over a gigabit per node of DOCSIS 3 and DOCSIS 3.1 bandwidth, that's still several dozen nodes' worth of saturated data transfer on a single fiber cable, so yes, it is *virtually* unlimited.
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post #1213 of 1223 Old 07-19-2016, 10:55 AM
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Comcast hasn't figured that one out yet. We still have at least 10 different Comcast systems, and they are all a bit different, and some are rebuilds, and some aren't. It's a complete and total mess out there. At least you'd think that they could harmonize the offerings among them even if they have separate physical headends. All they have closed are some of the stores, meanwhile they are "improving" customer service lol.
When Comcast acquired the Insight systems around here, they had to run them separately until they rebuilt their system as their system was 330MHz while the Insight systems were 450MHz. Part of that rebuild was running fiber between the headends, and once the rebuild was complete, they cut the Insight system over to their headend. Did the same in other areas of the state where they acquired systems adjacent to theirs.

CIAO!

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post #1214 of 1223 Old 07-19-2016, 12:59 PM
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I think the PRIMARY Reason PQ has suffered is because they are offering TONS MORE HD Content (Linear as well as VOD/PPV) and they've bitten off more than they can chew....esp. after adoption of Bandwidth Hungry CLOUD-DVR Changing to MPEG4 was a good choice...and eliminated many MPEG4-To-MPEG2 Converters after the C-Band SAT Receivers. But thus far COMCAST has REFUSED to adopt that OTHER technique that can save TONS of Capacity (at least 2:1), just like the other Cable MSO's are using: SWITCHED DIGITAL VIDEO for MOST of the LINEAR Channels:
https://en.wikipedia.org/wiki/Switched_video
BTW: VOD/PPV are ALREADY a form of SDV.....

Also note that IP Video Delivery ENCAPSULATED within the Video QAM Channels (vice I-N QAM Channels) is yet another form of SDV...presumably for lower cost:
http://www.btreport.net/articles/201...th-sprawl.html

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post #1215 of 1223 Old 07-19-2016, 01:03 PM
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That comment makes no sense. They have compressed more and more in order to put more bandwidth towards HSI and less towards linear QAM, and the quality has suffered as a result. What you're saying about putting bandwidth back on the QAM side would be moving backwards for the HSI network.
But didn't you say that they have been pushing fiber "deeper into the field" and generally increasing bandwidth overall? Essentially "making the pipe bigger". Why should they have to compress QAM more to increase HSI when the main pipe has supposedly gotten much bigger? If the pipe hasn't gotten bigger then I could totally see your point. They are making the QAM signals take up less bandwidth of the pipe so that bandwidth can be allocated to HSI. That would make sense. However, from what you've said and everything I've heard the pipe has gotten bigger in which case there wouldn't be a need to compress QAM more to increase HSI.

Maybe it does mean "moving backwards" for the HSI network but so what? If the HSI network can handle 4K easy but currently isn't being used it means, like I said before, the network utilization is way below capacity. Why not "move backwards" on the HSI network(which would still leave plenty of bandwidth for HSI) and improve regular QAM based TV. Fast HSI and good quality regular QAM picture quality.


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4k is not the only thing that's been using more bandwidth in the past 13 years, when we went from one QAM with 1.5mbps service to 8 or 16 QAMs with 150mbps service. Again, you're just mixing the QAM side and the DOCSIS side, and it doesn't work that way. They are basically two totally different things sharing a cable. You've got your whole argument backwards. The TV picture quality has dropped in part BECAUSE they have added so much HSI bandwidth over the past few years, and that's why there is so much capacity on the IP side for 4k.
True, 4K isn't the only thing that uses more bandwidth. However, it is the biggest user compared to anything else. Yes, two totally different things...SHARING A CABLE. That means they are sharing bandwidth. Increase the bandwidth to one and you have to decrease the bandwidth to the other.


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HELLO! As I've described about five times already, it's because they have been building out their HSI network at the expense of QAM bandwidth without using SDV or IPTV in order to gain bandwidth savings from not having to broadcast everything all the time, even on a smaller node system.
Like I said above, the pipe is bigger. If they had just left QAM where it was before and allocated all the new bandwidth to HSI then HSI would be better and QAM wouldn't have suffered.

Whatever is going on it needs to be fixed....FAST. For the cost the picture quality is simply unacceptable. Comcast is going to start losing business. The X1 UI is much better than DirecTV(again, my opinion) but picture quality is more important.



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Now you get it! You were *very* confused about it before. The key word on fiber is *virtually*. That means *relative to everything else*, i.e. relative to the bandwidth of the coax cable, and the bandwidth of the connections in the home used to transmit the data. The fiber to the node basically transmits that node's coax just over fiber, but the backbone of the network from the head end upwards can be built with 40gbps fiber, which even when they start pushing over a gigabit per node of DOCSIS 3 and DOCSIS 3.1 bandwidth, that's still several dozen nodes' worth of saturated data transfer on a single fiber cable, so yes, it is *virtually* unlimited.
I wasn't really confused about it. He made it sound like simply splitting the node without an overall increase in bandwidth was somehow helpful. If each new new has the same bandwidth (or at least more than half the original node) for 1/2 the number of people then yes, it makes sense.

Just out of curiosity, how many nodes does one head end typically feed? From my understanding a node is usually 1/2 mile or less from a home. According to the many techs I've talked to trying to resolve my issues the head end for my area is ~20 miles away from my home. If every home is really within 1/2 of a node then there must be a HUGE number of nodes fed by that head end.
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When Comcast acquired the Insight systems around here, they had to run them separately until they rebuilt their system as their system was 330MHz while the Insight systems were 450MHz. Part of that rebuild was running fiber between the headends, and once the rebuild was complete, they cut the Insight system over to their headend. Did the same in other areas of the state where they acquired systems adjacent to theirs.
That must have been a while ago! Our bad systems are 625mhz or 650mhz, there are one or two 750mhz systems, and then the rebuilds are 860mhz.

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I think the PRIMARY Reason PQ has suffered is because they are offering TONS MORE HD Content (Linear as well as VOD/PPV) and they've bitten off more than they can chew....and thus far have REFUSED to adopt that OTHER technique that can save TONS of Capacity (at least 2:1), just like the other Cable MSO's are using: SWITCHED DIGITAL VIDEO:
https://en.wikipedia.org/wiki/Switched_video
Yeah, that's exactly the problem. So if you do the math out on an 860mhz cable system, which right now is basically the highest frequency HFC plant you can practically run (Cox has a lot of 1ghz systems, but they are finicky, and even 1ghz doesn't fundamentally solve the problem alone), there simply isn't enough bandwidth there to push out 200 HD channels in good quality, as well as the internet and VOD bandwidth that everyone wants without SDV. No matter how small you push the nodes, having that much bandwidth tied up with linear channels, about 150 of which are rarely watched, just doesn't make sense. The 2:1 comparison is about right, as you need about 50 HD channels delivered linearly, but the remaining 150 or so can be put into the bandwidth of about 50 linear channels using SDV with decent sized nodes. So where Comcast is at 120 HD's that look like crap, with SDV, you can deliver 200 HD that look great, and with SDV you now get a lot more bang for your buck with deeper fiber, as you're able to reduce the number of QAMs needed to provide SDV and VOD in addition to delivering more internet bandwidth the deeper you push the fiber.

Comcast seems to have decided that they aren't investing in TV anymore until they go entirely IP, but that is going to take years at best just to make the HD stuff IP, whereas SDV works with existing equipment, and could even be combined with MPEG-4 to offer outstanding PQ as well as capacity savings. It's so frustrating that they have so much bandwidth, and should be able to completely blow satellite out of the water, and yet DirecTV is still pretty much the gold standard over cable, as cable has no leveraged the inherent advantage that they have in terms of bandwidth being delivered individually to each node, and the ability to use SDV to provide effectively an unlimited number of channels, with capacity based on the number of subscribers and TVs on the node, not the number of channels available. SDV would also help Comcast to transition to IP, as it frees up more capacity for DOCSIS 3.1 so that they could provide higher HSI bandwidth, as well as 4k and HDR content via IPTV.
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post #1217 of 1223 Old 07-19-2016, 01:25 PM
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4K is hardly any threat to Bandwidth Consumption TODAY and probably not for another FIVE YEARS before there is a SIGNIFICANT number of 4K Channels....
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That must have been a while ago! Our bad systems are 625mhz or 650mhz, there are one or two 750mhz systems, and then the rebuilds are 860mhz.
Yes, that was some time ago. I even had the pleasure of helping map some of TCI's system (TCI eventually became Comcast).

The 750MHz systems shouldn't be all that bad to rebuild to 860, but the 625 and 650 ones will really be a challenge. Guess that's what they get the big bucks for.

CIAO!

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4K is hardly any threat to Bandwidth Consumption TODAY and probably not for another FIVE YEARS before there is a SIGNIFICANT number of 4K Channels....
We're looking more at OTT SVOD consumption, but even that is going to take a while to scale, since there are relatively few users, and those users often aren't watching 4k content.

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Yes, that was some time ago. I even had the pleasure of helping map some of TCI's system (TCI eventually became Comcast).

The 750MHz systems shouldn't be all that bad to rebuild to 860, but the 625 and 650 ones will really be a challenge. Guess that's what they get the big bucks for.
What pisses me off is that they did several of the systems. Yeah, it's a lot of work, but this is 2016. All the systems should be 860mhz. Period. And all new equipment going in today should be a MINIMUM of 1ghz, even if the overall plant is going to be operated at 860mhz. They spent a LOT of time on the system where my parents live with the rebuild. They were out there every day for months between 0000 hours and 0600 hours during the downtime window. Their system is now rock solid. X1 has issues, and their video compression still sucks bigtime, but the plant itself is rock solid, and very reliable, and consistently delivers 175mbps on an 8x4 eMTA (the system has 16 DOCSIS QAMs).

The system I'm on now is a 625mhz system, but apparently they had issues holding a QAM at 615mhz, as some subs couldn't get it and would complain that channel went missing, so based on what the tech told me, I believe the plant was only running at 594mhz, with the last QAM being 591mhz. So now the DOCSIS channels got moved from the 300's to 579mhz through 621mhz, I guess the logic there is that most people won't notice if they lose a few DOCSIS QAMs and the other users on the node will just even out the load lol. Just hope the ones who can't hold the last 4 QAMs aren't on Blast! on a system that only has 8 DOCSIS QAMs in the first place. That probably bought them 4 more QAMs that are reliable for video in the 300's now that the DOCSIS channels are half on the sketchy QAMs.

Why are they playing games with a failing 625mhz relic in one area, while another has a shiny new 860mhz plant that's really rocking? Meanwhile, our overbuilder has a relatively new 750mhz plant that they're operating with effectively the capacity of a 325mhz plant, since they have 70 channels that are squandered with analog.
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We're looking more at OTT SVOD consumption, but even that is going to take a while to scale, since there are relatively few users, and those users often aren't watching 4k content.



What pisses me off is that they did several of the systems. Yeah, it's a lot of work, but this is 2016. All the systems should be 860mhz. Period. And all new equipment going in today should be a MINIMUM of 1ghz, even if the overall plant is going to be operated at 860mhz. They spent a LOT of time on the system where my parents live with the rebuild. They were out there every day for months between 0000 hours and 0600 hours during the downtime window. Their system is now rock solid. X1 has issues, and their video compression still sucks bigtime, but the plant itself is rock solid, and very reliable, and consistently delivers 175mbps on an 8x4 eMTA (the system has 16 DOCSIS QAMs).

The system I'm on now is a 625mhz system, but apparently they had issues holding a QAM at 615mhz, as some subs couldn't get it and would complain that channel went missing, so based on what the tech told me, I believe the plant was only running at 594mhz, with the last QAM being 591mhz. So now the DOCSIS channels got moved from the 300's to 579mhz through 621mhz, I guess the logic there is that most people won't notice if they lose a few DOCSIS QAMs and the other users on the node will just even out the load lol. Just hope the ones who can't hold the last 4 QAMs aren't on Blast! on a system that only has 8 DOCSIS QAMs in the first place. That probably bought them 4 more QAMs that are reliable for video in the 300's now that the DOCSIS channels are half on the sketchy QAMs.

Why are they playing games with a failing 625mhz relic in one area, while another has a shiny new 860mhz plant that's really rocking? Meanwhile, our overbuilder has a relatively new 750mhz plant that they're operating with effectively the capacity of a 325mhz plant, since they have 70 channels that are squandered with analog.
And down the road here in Clinton, we are looking at some channels that are size-reduced! Yes, about 3/4 screen equal border all around roughly. You have to re-size your picture to view them right and there is no HD counterpart to go to. Just ridiculous for almost $200/mo.
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And down the road here in Clinton, we are looking at some channels that are size-reduced! Yes, about 3/4 screen equal border all around roughly. You have to re-size your picture to view them right and there is no HD counterpart to go to. Just ridiculous for almost $200/mo.
That's standard for SD channels. You need a video processor or something to deal with that. Sadly, they don't have that issue over in Madison, as they can just tune the HD version. I don't get how Branford and Norwich got upgraded but Groton and Clinton didn't. Go figure.
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That's standard for SD channels. You need a video processor or something to deal with that. Sadly, they don't have that issue over in Madison, as they can just tune the HD version. I don't get how Branford and Norwich got upgraded but Groton and Clinton didn't. Go figure.
Yes, that is what it is and in Clinton plenty that should be HD like HBO2 and Flix. BUT, we do get to pay the same high price as the Branford folks. Lucky us!
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Yes, that is what it is and in Clinton plenty that should be HD like HBO2 and Flix. BUT, we do get to pay the same high price as the Branford folks. Lucky us!
Yeah, same in Groton. Same prices as Branford. We're literally getting 30% less product. ESPNU is the big missing channel. Back when AJAM was around, we didn't have that at all, Branford had it in SD (very good looking SD, I might add).
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