# Noob Questions



## Tbay_7302 (May 9, 2006)

Ok, I'm completely green as to how any satellite companies' "boxes" process the signals sent to them via the satellite. What type of internal hardware/software do they use to perform this? If anyone knows any type of information like this or knows where I can find such information, it would be greatly appreciated.
Thank you in advance for any and all help.


----------



## James Long (Apr 17, 2003)

:welcome_s TBay

It's unneeded knowledge if you just want to watch TV. But it can be a neat hobby looking through FTA channels and just understanding how the picture gets from there to here. Most channels on Dish and Direct are scrambled, so having basic knowledge won't get you "free TV" (with the exception of a few channels). We do not discuss descrambling TV here. (That will get you banned really quick.)

Anyways, welcome! You might also head on over to the FTA forum here for people interested in the "how does it work".

(Thread moved from E* DVR forum since it is not Dish Network or DVR specific.)


----------



## Tbay_7302 (May 9, 2006)

Not trying any tricks to get anything free or illegally, just looking for some basic knowledge as to what makes 'em tick. Thanks for the advice and the, I don't wanna step on any toes, just lookin for a little insight.
Thanx


----------



## FTA Michael (Jul 21, 2002)

Here's a link to start: http://en.wikipedia.org/wiki/DVB

Also, you can head to your local library, which probably has a bunch of 15-year-old satellite TV books on its shelves. Most of the basics are the same, and these older books still provide good background.


----------



## Tbay_7302 (May 9, 2006)

Thanks Carload for the info hookup. It actually led me to a new question though. Is there a feasible way for an MHP Program or App to differentiate two signals being sent to the same cable box and tell said cable box which signal to run? Thank you for any assistance.


----------



## FTA Michael (Jul 21, 2002)

MHP Program? Maybe my coffee wore off, but what's that?

Two signals to same cable box could be sent on different frequencies, or could contain different digital information. For an obvious example, an internet packet can flow through several cable boxes before it reaches "its" cable modem.


----------



## harsh (Jun 15, 2003)

carload said:


> MHP Program? Maybe my coffee wore off, but what's that?


I'm betting on "Multimedia Home Platform".

Personal computer based satellite tuners seem to be more popular in Europe.

I think part of the answer to the question is going to come from a study of what a "diplexer" does.

To my knowledge, there are no combined "Cable Card"/DVB receiver cards for multimedia computers. Windows XP MCE does not support DVB cards at this time.

As always, the key to getting a correct answer the first time is to post what your goal is rather than asking pointed questions about how you think it might work.


----------



## Tbay_7302 (May 9, 2006)

harsh said:


> I'm betting on "Multimedia Home Platform".
> 
> Personal computer based satellite tuners seem to be more popular in Europe.
> 
> ...


Thats right and through the inof i got on sat. boxes/cable boxes it said they all use an MHP for their programming. AM I wrong?
I'm not trying to use anything with my computer, just television.
My goal is to find out how signal processing works within satellite/cable receiver "boxes" and what they use to differentiate signals. Thank you for your help.


----------



## harsh (Jun 15, 2003)

Tbay_7302 said:


> Thats right and through the inof i got on sat. boxes/cable boxes it said they all use an MHP for their programming. AM I wrong?


You are misinformed. Most cable and satellite boxes use Linux.


> I'm not trying to use anything with my computer, just television.


Subscription satellite is not on the table at this time. There is limited Free to Air (FTA) programming available to DVB cards, but nothing supported by MHP computers.


> My goal is to find out how signal processing works within satellite/cable receiver "boxes" and what they use to differentiate signals.


They don't need to differentiate anything as they don't occur in the same medium. There are two or three technologies employed in each medium and more on the way.

The first thing you need to know is that it is mostly "scrambled". There are a couple of "Cablecard" cable tuners available that, with the assistance of a Cablecard leased from your cable provider, will allow you to tune cable content. Some of them are even dual tuner.

Practically speaking, I'm not sure any of these solutions is going to be as straightforward and easy to use as the respective DVR offerings. The major issue with doing TV via MHP equipment is that the content owners don't like the idea that their content is going to be recorded onto common personal computers in such a manner that it can be easily shared. Both satellite and cable have implemented copy protection schemes to prevent users from archiving PPV and other exclusive content. Most of the focus is on the HD content at this time.

In summary, if you're lookiing to do MHP, you need to do cable with a suitable Cablecard enabled tuner. For a glimpse at some of the stuff that is going on, check out this site: http://www.byopvr.com


----------



## Tbay_7302 (May 9, 2006)

harsh said:


> They don't need to differentiate anything as they don't occur in the same medium. There are two or three technologies employed in each medium and more on the way.


Maybe I misworded that, I meant how do the tuner boxes that send the satellite signal to your television differentiate between diferent signal(I.E. The signal that's supposed to go to your neighbors house and the one that goes to your house). Or am I again mistaken and they just descramble one signal differently on each box? 


harsh said:


> In summary, if you're lookiing to do MHP, you need to do cable with a suitable Cablecard enabled tuner. For a glimpse at some of the stuff that is going on, check out this site


I'm not looking solely into MHP, I just thought thats what was used universally. I'm interested in all around knowledge of how these systems work so thank you for the lead and all your help. That site is giving me a lot of useful info and hopefully it'll be a great asset to me. Thank you


----------



## FTA Michael (Jul 21, 2002)

Dish tuner boxes are controlled with satellite signals from Dish. (I'll stick to that example to make these sentences clearer.) When you call a Dish CSR to subscribe to WPIX, the CSR hits a key that almost-magically causes a signal to be sent from the uplink station to all tuners watching that satellite. That signal says, "If you are tuner number XYZ123ABC456, then you may treat WPIX as a subscribed channel." All other tuners ignore the message, but the matching tuner now allows you to view WPIX.

On the other hand, if the audit team hates you or your check bounces, the system can send a signal that says, "If you are (that tuner), begin treating all channels as unsubscribed."

For digital cable, the process is similar but goes over the cable system, of course. For non-digital cable, mechanical devices (filters etc.) block or clear unsubscribed/subscribed channels.


----------



## Tbay_7302 (May 9, 2006)

carload said:


> Dish tuner boxes are controlled with satellite signals from Dish. (I'll stick to that example to make these sentences clearer.) When you call a Dish CSR to subscribe to WPIX, the CSR hits a key that almost-magically causes a signal to be sent from the uplink station to all tuners watching that satellite. That signal says, "If you are tuner number XYZ123ABC456, then you may treat WPIX as a subscribed channel." All other tuners ignore the message, but the matching tuner now allows you to view WPIX.


So Itake it then that tuners work by distinguishing between multiple satellite signals rather than decoding one signal in a bunch of different ways. Right?
If so what kind of hardware would the tuner use to process this information?
Thank you


----------



## James Long (Apr 17, 2003)

About the same hardware that a over the air digital TV tuner uses to turn bits into pixels. Except on OTA there usually isn't any scrambling or access restrictions involved.

Each transponder (or OTA signal) carries a digital carrier with many streams of information multiplexed within it. Some of those streams are audio, some are video, some are data. One of the streams is a repeating table pairing audio and video streams into channels.

On E* the DishCD and Sirius channels are paired audio and data. There are several grouped audio/video/data channels used within Dish Home (for Bloomberg, CNN and HRTV). There is also a lot of data to support the receiver - EPG streams so one knows what is on now and next, tables to tell the receiver what transponder every channel is on and if that channel should be displayed, and of course encryption and permission systems (since E* is a subscription system and not FTA).

What makes a reciever know whether or not to unscramble a channel? Instructions sent to each specific reciever via satellite. If E* wants to kill a specific receivers ability to descramble a specific channel they can. As long as there is a satellite connection on any transponder in the system E* maintains control over your receiver. They can even force DVRs to record five minute ads in the middle of the night.


----------



## FTA Michael (Jul 21, 2002)

Tbay_7302 said:


> So Itake it then that tuners work by distinguishing between multiple satellite signals rather than decoding one signal in a bunch of different ways. Right?
> If so what kind of hardware would the tuner use to process this information?


Well yes, each satellite sends multiple signals, and multiplexed within each signal you'll usually find several channels. If you search the web for FTA satellite information, you'll eventually find lots of information about the technology involved. Dish uses that sort of technology plus encryption.

For deep, rich subjects such as this, nothing beats a book. If you can't find a decent book on satellite TV, start browsing the web here: http://en.wikipedia.org/wiki/Satellite_television


----------

