posted 07-02-2003 12:43 PM                       

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Together they cover the USA and parts of Canada with a 70 megawatt signal

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Those satellites must have quite the nuclear reactor to generate that kind of power. Methinks the power is somewhat lower.

posted 07-02-2003 02:00 PM                       

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Broadcasting at 3,000 Watts

XM Roll will operate in geosynchronous orbit at 85 degrees west longitude over the United States. Like Rock, which is stationed at 115 degrees west longitude, it carries a digital audio radio payload built by Alcatel Space Industries (NYSE: ALA) that features two active transponders, each with 16 active (and 6 spare) 228-watt amplifiers generating some 3,000 watts of radio frequency (RF) signal power, making them the most powerful commercial transponders ever built, XM said.

Rock and Roll each have two wings with five panels of solar cells to generate power in space. When fully deployed, the wings span 132.5 feet. The satellites, with a 15-year expected lifespan, were manufactured by BSS, a unit of The Boeing Company (NYSE: BA). XM said its third satellite, a spare, is undergoing final testing.

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The company's XM-2 satellite, dubbed "Rock," was sent into orbit by Sea Launch on March 18.

Each of the XM satellites weighs 10,322 pounds (4,682 kilograms) and are designed to operate 15 years. When fully deployed, the satellites' electricity-generating solar arrays stretch more than 134 feet (40 meters), which is longer than the wingspan of a Boeing 757.

The satellites are equipped with two transponders and each of those are capable of broadcasting 3,000 watts of radio frequency signal power, making them the highest power commercial transponders ever built, according to Boeing. That means that on the ground the receiving antennas can be very small.

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posted 07-03-2003 01:49 AM                       

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Their commercials with performers like David Bowie and Snoop Dogg

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posted 02-04-2007 10:51 PM                    

quote: Pravin Ratnam

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I was going car shopping and I was amazed at how bad the sound quality is for both Sirius and XM.

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Both XM and Sirius run all of their satellite radio channels at bit rates of merely a puny 96 kilobits per second. Pretty bad.

HD Digital Radio is even worse. The "HD" in the brand name is an extreme insult to anyone with any level of intelligence at all. At best, a HD Digital Radio station will be broadcast at 96kb/s. But very often the bitrate is dumped down to a mere 64kb/s. On top of that, thanks to some nice greedy, typical corporate politics, HD Digital Radio uses an inferior "PAC" codec that is not as efficent as the codecs used by XM and Sirius.

Sit back and relax in the swirling, metallic, brazzy and harsh quality of ultra-compressed digital radio! Yay!


I am very confident in my predictions the Internet will eventually lay waste to standard paradigms of television broadcasting. When Internet bandwidths achieve average connection speeds of 30Mb/s to 100Mb/s (which will happen in just a few years) you will see the state of over the air broadcasts, cable and satellite all change very radically.

The same is now going to happen to radio. That's because standard over the air radio and satellite radio cannot step up to the demand of improving. The guys currently running the business all subscribe to the bankrupt "lets do as little as possible" ethic when delivering the product to the customer. Those very very low bit rates are going to end up costing them dearly.

Lots of different radio stations already make it possible to listen to them via an Internet connection. When high bandwidth broadband Internet is common, what is it going to hurt to allow people to listen to the music in full LPCM quality or a great deal better (like 5.1 24/96)?

Technologies like WiMax will soon be rolled out and start covering the entire nation (and much of the rest of the world) with very fast broadband capability. Currently our telecoms are in a lethargic state of comfort, not quick to do anything to make American customers benefit from much higher quality service. They won't be able to do that much longer.

In the long run, your car, your phone, your notebook and perhaps some other digital devices will be able to get online anywhere anytime at very high data rates. That will make any form of video or radio possible. And the low bit rate stuff is just not going to last.