Receiving Satellite Television - Especially NASA TV in the New Digital Format
Jack Dunn - Mueller Planetarium

Let's start with satellites, dishes and receivers.

The main satellite signal delivery system for many years was what is called "C-Band." This is the "BUD" (Big Ugly Dish), system. Dishes were anywhere from 6 to 10 ft. in diameter. This was how most television was delivered to local stations and cable providers after the broadcasters went away from phone lines.

For years, NASA-TV has been a C-Band signal.

There was a need for scrambled or encoded signals. Providers like HBO didn't want the average viewer to be able to watch for free if they just set up a dish and receiver. General Instruments Corporation introduced DigiCipher encoding some years ago. Long before cable systems got these abilities, satellite receivers with DigiCipher could call in and get pay-per-view programs and other addressable features. That is, they could actually address individual receivers. Integrated Receiver Descramblers (IRDs) became common for those who bought satellite receivers for home and business reception of these signals. The signal off the satellite was often superior to anything you saw on broadcast television.

The DigiCipher system included digital audio but was not really compressed. This also accounted for the outstanding picture quality.

Some years ago, GI upgraded the system to Digicipher II, which had some further enhancements.

One of the big issues in broadcasting is bandwidth. Television signals need more than radio signals. And broadcast space is always at a premium. Engineers realized they could fit more signals in the same space by digitally compressing them. This is the basis of digital cable. But long before digital cable, systems were created for satellite.

The small dishes (only a few feet in diameter) operated with digital compression and on different frequencies than the C-Band. That's where DISH Network and it's competitors reside. One small dish never has to move. It gets all it's channels from one satellite. Then General Instruments introduced 4DTV. This digital system still used the BUD and C-Band, but more channels with less compression gave it a good signal. Another system which also uses the C-Band and BUD is an "Mpeg2" system. This compression is similar to the video compression found in computer systems. 4DTV and the Mpeg2 system are not compatible and take different receivers. And of course a small dish system takes another completely different receiver than the one for C-Band.

The question of whether you would need a new LNB (the receiving device out on your dish) for a digital system with C-Band varies with what you have. Our 20 year old LNB is fine for 4DTV, and if it handles that, it probably handles Mpeg2 fine. But this is where you would have to experiment. Don't just take a dealer or any salesperson's judgment on this without trying it.

Motorola bought General Instruments so you'll now find their stuff under the Motorola brand. You can buy an IRD like we did with standard C-Band and the shorter KU-Band reception and 4DTV built-in. To get the mpeg2 signals on C-Band, you have to buy a separate "add-on" receiver. But you still need the original IRD, if you want to have a moveable dish. (You want a moveable dish if you want to see signals from more than one satellite. And there are 4DTV and mpeg2 signals on a number of satellites).

Ok, so you want to see NASA TV. If, and I have no way of knowing the answer right now, DISH network or one of the other small dish systems decides to carry NASA TV once it goes digital (they do carry the single NASA TV channel right now - May 2005) you could buy or lease one of their systems.

You aren't getting NASA TV directly. The DISH network office would receive the mpeg2 signal off C-Band, then resends it back up to their satellite and you'd get it with all their other DISH network channels. But note that means the signal has been compressed twice. Your quality may vary. But it's probably better than the internet signal.

To receive NASA TV directly, you need a BUD and some sort of IRD and then the mpeg2 decoder. I should mention that mpeg2 is eventually going to be replaced by mpeg4 as systems head towards HDTV, but who knows what NASA will do then. Just realize it's out there. And then I will probably have to buy a new LNB.

So, don't buy a receiver for DISH or some other small dish system and think you can hook it to a BUD and get NASA TV. There are providers for the IRDs, but I would not go to a Radio Shack, Best Buy or Circuit City or similar store for this. They only carry the small dish systems. You may buy one from them if NASA TV shows up on the small dish. Otherwise, don't bother. And asking questions of employees at a discount chain story is risky. Now if we can find out if DISH and Direct TV are carrying NASA TV, you only have to invest in one system. However, we don't know if they'll carry all four channels of it. The folks I discussed this with in the satellite industry thought DISH or Direct TV might actually carry all four channels. After all, they get to claim they carry 4 more channels for their subscribers and it costs them nothing. But I wouldn't go out and buy a small dish or lease it till we know for sure what they are going to do. And, if you are like us on the University campus, putting up anything new would be a pain from the bureaucracy. I hope all this helps you understand the current state of satellite tv.

The author has been on the advisory board of SCOLA (Satellite Communications For Learning) associated with Creighton University for many years. They receive satellite television news from many countries in the world and then rebroadcast this up to a single satellite as a service to which Universities, schools and cables systems subscribe. So they also use four channels digitally on C-Band in a similar system to what NASA is implimenting. It is the older mpeg 1 system, but the basic operation is the same.

Here's a SCOLA link so you can see how they operate:
http://www.scola.org/eoneCommerce/Portal

Here are some links to dealers and information which might be helpful.
http://skyvision.com/

C-Band FAQ
http://skyvision.com/pages/information_center/faq.htm

Free-to-air Mpeg2 FAQ
http://skyvision.com/pages/information_center/mpeg_faq.html

History of Satellite Television
http://www.sbca.com/mediaguide/history.htm

with an overview of the various services at:
http://www.sbca.com/mediaguide/satservices.htm