What are the fundamental differences between tv and internet, and their transmission?

[Zellio2008]

I've tried looking this up, but all I can find are a bunch of idiots who insult one or the other.

I want to know why the two can be sent differently, and why satellite can broadcast tv better and internet worse, and cable vise versa.

I know some of it, but I want to know the full reason. I HAVE TO KNOW , I have a thurst for knowledge.

I currently have Directv hd, premier package with sports, and the 5 channel hd extra stuff... When you add the locals, mpeg 2s, my sports channels, and my sports, basically anything I can currently view, I have 127 hd channels I can actually watch and view things at almost any point. (And yes, I still wish I had more premium channels, I like moviews better then sports , but I kinda bitch no matter what ). I have it in 5 rooms, 1 room has Charter hd basic (I use 6 connections, and my room gets another HD DVR, and I only have an 8 connection splitter, too bad charter room).

Anyway, my Charter service only gets a sum total of ... 7 hd channels. And if I suddenly lost my mind and wanted to get Charter, I'd end up with 35 total hd channels. I was only joking with the Directv thing (the whole acting full of myself part), I mean I pay $140 PER MONTH so I feel I should bitch for more premium channels, but damn, if I had charter I'd be crying every day........

But then we turn the tables...

I currently have Charter Internet Max. Which means 20/2. And a 250 gig cap (Which they don't totally enforce). If I got local satellite internet, I'd have the pro plan from Hughesnet for what I currently pay for cable (1.2 mBIT/200 kBIT, and like a 200 meg download limit per day??)

I know some reasons why both are different, but not the full story, and I want to know. Go into as many details as possible. I don't want the 'bandwidth explanation for dummies' here.

 

[JosephB]

In a nutshell there is little to no difference between digital TV transmission and broadband internet. They are both simply digital packets of bits transmitted from one location to another.

Now, as to why there are such disparities between cable internet and satellite internet and satellite tv and cable tv, that's more complicated, and is basically going to turn into a bandwidth for dummies.

Cable TV is structured such that all of their services must be provided on a single coax. Most cable companies have hybrid fiber systems meaning that they have fiber to your neighborhood, or maybe even your block. Beyond that, though, you are sharing one coax with everyone on that node. That means that one coax has to carry EVERYONE'S 20mbit internet, telephone services, PLUS all of the channels offered ALL AT THE SAME TIME

Now, compare that with satellite: Not all the channels that DirecTV offers are crammed down the coax at the same time. Because your dish serves only your home, the receiver can communicate with the dish and have only the channel(s) you are trying to watch or record sent down the coax at any particular time. This means DirecTV is not limited by the bandwidth of the coax cable, they are only limited by the bandwidth of the satellites in space (which is MUCH MUCH MUCH MUCH higher than the coax)

Now on the flip side, satellite internet services are limited because Hughesnet has limited satellite capacity and many many customers. It's the same problem as the cable company, only the 'node' is much further up the line. All of the satellite internet customers are sharing the bandwidth available on the satellite. Satellite bandwidth is also MUCH more expensive, so they simply have less of it available. That is combined with the fact that there is a smaller market for satellite internet services, so they do not reach the same economies of scale that a company such as Comcast does in terms of internet access.

 

[kbhouser]

I've tried looking this up, but all I can find are a bunch of idiots who insult one or the other.

I want to know why the two can be sent differently, and why satellite can broadcast tv better and internet worse, and cable vise versa.

I know some of it, but I want to know the full reason. I HAVE TO KNOW , I have a thurst for knowledge.

I currently have Directv hd, premier package with sports, and the 5 channel hd extra stuff... When you add the locals, mpeg 2s, my sports channels, and my sports, basically anything I can currently view, I have 127 hd channels I can actually watch and view things at almost any point. (And yes, I still wish I had more premium channels, I like moviews better then sports , but I kinda bitch no matter what ). I have it in 5 rooms, 1 room has Charter hd basic (I use 6 connections, and my room gets another HD DVR, and I only have an 8 connection splitter, too bad charter room).

Anyway, my Charter service only gets a sum total of ... 7 hd channels. And if I suddenly lost my mind and wanted to get Charter, I'd end up with 35 total hd channels. I was only joking with the Directv thing (the whole acting full of myself part), I mean I pay $140 PER MONTH so I feel I should bitch for more premium channels, but damn, if I had charter I'd be crying every day........

But then we turn the tables...

I currently have Charter Internet Max. Which means 20/2. And a 250 gig cap (Which they don't totally enforce). If I got local satellite internet, I'd have the pro plan from Hughesnet for what I currently pay for cable (1.2 mBIT/200 kBIT, and like a 200 meg download limit per day??)

I know some reasons why both are different, but not the full story, and I want to know. Go into as many details as possible. I don't want the 'bandwidth explanation for dummies' here.

If you are thirsty for knowledge, you will catch more flies with honey...

First of all, if you want as many details as possible, you might want to leave off the "I don't want.." part of your question, as it indicates that you are not open to explanations that include things you know. It is hard to say what you know and what you don't know, since you are asking a fairly noob question.

TV is a broadcast medium. If you temporarily lose the signal, it is gone for good. You can't ask for it to be resent. The picture glitches and returns to normal, but the missing time slot is gone. The internet protocol (IP) was designed for the military, to allow individual packets to be sent from point to point to point over unreliable channels that could be lost for whatever reason (e.g. war time destruction).

TV over the internet uses packets that could arrive out of sequence or even not at all. Broadcast TV over the air (or by cable or satellite) is a continuous stream. Internet packets require handshakes (two way communication) to insure the packets arrive OK. If there is a reliable internet connection with sufficient bandwidth, then the overhead of packetization is not an issue, up to a certain point.

Your question revolves around bandwidth, so while the following may appear to be "for dummies", it may answer your question. If not, then you might want to rephrase it based on your understanding of bandwidth.

1. Satellite TV has a lot of bandwidth (channels) because of the number of frequencies (transponders) involved and the number of satellites your dish could be pointed at. We all get access to the same number of channels, depending on how much we pay. Adding new customers doesn't put increased demands on bandwidth. It is a one to many, or broadcast, medium.

2. Satellite Internet has a certain amount of bandwidth too, but it is shared. Each user has access to a single transponder on a single satellite. Each internet connection wants a little slice of that bandwidth, so as you add customers, more bandwidth is consumed, and restrictions are ultimately placed on users who want to use more than what is "fair". So while the technology is similar, you can't have access to my "channel", and I can't have access to yours. Think of it as one to one, or narrowcast.

3. Cable is also a fixed bandwidth system, the actual amount depends on your cable company. Do they have fiber or coax? How recently did they upgrade the system? Are they carrying analog or digital channels? HD channels, while compressed, are still bigger users of bandwidth than digital SD channels. Cable internet places more demands on the system, but they can use concentrators in individual neighbor hoods so the shared part of the cable is limited to smaller areas, unlike shared users on a satellite transponder. Since cable systems are local to a city, there is no sharing across the country as there is with satellite.

So satellite can do TV better than internet because the stream of bits is continuos and predictable. Cable has better internet capacity, and the limitations of packet delivery are less of a problem. Satellite internet is an expensive alternative for those who can't get ground based internet faster than dialup.

I hope I answered your question, if not, maybe you could be more specific.

 

[Pepper]

The main reason satellite Internet is so bad, aside from the bandwidth limitations, is the fact that Internet communications is in both directions.

22300 miles + in each direction from the source to the satellite and then to you isn't really noticeable in a one-way communication such as watching TV. But just try doing something interactive such as a VOIP phone or an online game.

 

[JosephB]

kbhouser pretty much hit the point I wanted to make. satellite is a broadcast medium. everyone in the country gets the exact same packets (generally..we'll forget about spot beams for this). This makes it great for TV since there's no difference in HBO for me in Alabama or you in California.

Cable is more point-to-point. It's great for stuff like internet because you have a return path, but more importantly, your internet doesn't get broadcast to everyone in the country..just everyone on your block.

Cable's problem is they're trying to cram too many services on one coax. When they move over to switched digital TV, then it'll work more like satellite where your house requests the channel(s) you want to watch and they remove all the others from the line.

 

[HDinCincy]

kbhouser rules!

 

[sundude90]

Now that I know how the cable internet work. How does DSL work?

 

[Pepper]

DSL works basically the same way by allocating part of the available bandwidth on the line to your house for data. Instead of video, the other thing on the line is voice/dialtone. The filters you have to install keep you from hearing the high-frequency noise when you're on the phone, plus filtering out high-frequency sound that would corrupt the data.

A difference between DSL and cable is that while the coax may be shared amongst all the homes in your neighborhood, the wire from you to the DSLAM is dedicated to you.

 

[kbhouser]

DSL works basically the same way by allocating part of the available bandwidth on the line to your house for data. Instead of video, the other thing on the line is voice/dialtone. The filters you have to install keep you from hearing the high-frequency noise when you're on the phone, plus filtering out high-frequency sound that would corrupt the data.

A difference between DSL and cable is that while the coax may be shared amongst all the homes in your neighborhood, the wire from you to the DSLAM is dedicated to you.

Note that the available bandwidth was there all along, but never used. Phone lines were designed for voice, and only a narrow range of audio (30-3000Hz). Attenuation occurs as you increase the frequency of the signal or the length of the line. Fatter phone lines reduce the attenuation.

So, the problem with DSL is the signal strength falls so quickly with distance, such that while you may have decent voice quality, the higher frequencies can only go so far. That is why you won't get DSL service more than 18000 feet from the local Telco, unless they put in a loop extender or bring fiber closer to your house.

 

[berck]

One thing not mentioned about Satellite internet is the fact that the Satellite system has an inherit delay of about a half second in one direction (transit to satellite 0.25 seconds and back down, another 0.25 seconds). Internet protocols don't like this at all. IP likes to get handshaking going, and if two way internet is required, the hardware is setup to do some type of faking of the hand shaking to get the data rates higher. It helps if the return path is a modem so to speed this up, but there still can be issues at times.