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(Short-, Medium-, Long)wave Radio Meets Digital Stereo
cryptec writes "Today shortwave radio will have some new life pumped into it as the German broadcaster Deutsche Welle will be the first full time shortwave broadcaster of DRM (Digital Radio Mondiale). DRM is a full stereo fully digital broadcast system. The quality of the broadcasts are close to that of FM radio. For samples check out this link." Akai adds this link to an article in the San Francisco Chronicle with some more information, like the involvement of the BBC and Voice of America in this undertaking.
I don't think that's a popular acronym around here.
The goatse guy for president. Win one for the gaper!
RANGE man, range! worldwide FM quality shortwave is gonna be cool.
My potato gun was confiscated by the United Nations. They said I wasn't allowed to have weapons of mash destruction.
Say what you want to about the utility of digital music over short-wave, I think it's a fascinating development. It's just another big application of Peer to Peer technology, one completely bypasses the internet. It's not just music that can be broadcasted this way - files can be sent and they could contain anything - newspapers, video, software, worms - and they could come from anyone with enough power to broadcast them. If the use of such technology becomes widespread enough - look for this becoming just another way to suck data into your computer, no matter how isolated you happen to be.
The flag just makes more sense than the constitution. - Judas Gutenberg
Sure. You see, it's far cheaper to use as-yet-experimental state-of-the-art technology than to continue using transmitters and technologies that have been in use for decades and that are well understood and easily serviced by thousands of technicians.
The new transmitters will no doubt be fitted in, say, a few weeks. Then, in about three months, just about every household in North America will have bought the new receivers, and switch to tuning in small transistor radio sets to BBC broadcasts, instead of, say, surfing pornography or using AOL. Once the BBC starts digital broadcasts, well, no one will want, or need, broadband internet connections!
Notice that the bitrates used in these AAC streams are wayyyy too high to ever be transferred over a dial-up connection. Even IF PCs could be equipped with AAC decoders, or similar codecs, such as ogg vorbis, the bitrates needed, some even exceeding 22 kilobits per second would prove a lethal hurdle for people who would want to listen to a stream using such a "magical" codec on their PCs..
Plus, other, existing, methods of delivery for digital radio, such as satellite, are clearly inferior to this new technology.
</SARCASM>
SCO employee? Check out the bounty
There are in the US people who actually live so far out in the middle of nowhere that shortwave is the only option for radio unless they want to put up a huge antenna.
Its also a fairly widespread hobby. Starting cost can be as low as $10 for a garage sale world band radio up to several thousand for the latest in equipment.
Its pretty fun being able to hear programs from austalia, india, or wherever someone can muster a few kilowatts to bounce a signal off the ionosphere.
Coded Orthogonal Frequency Division Multiplexing
It's similar in purpose to CDMA. It is spread spectrum, sorta. It uses many narrowband carriers transmitting in parallel. The data transmitted on the subcarriers uses forward error correction coding, it's sorta like RAID1 for radio. They can also use tricks like sending the more important data at lower speeds. It's a pretty robust system, but it was mostly designed to combat multipath fade at VHF and above.
I've had enough abrasive sigs. Kittens are cute and fuzzy.
Well, PSK31 doesn't have error checking like DRM does. DRM has configurable "robustness modes" for use in more or less noisy environments.
Did you ask your friend to put the PSK31 signal on the speaker? The really cool thing about PSK31 is that your computer can copy a signal you can't even hear.
(For anyone who's wondering, we're still talking about digital radio. PSK31 is a modulation technique for text which fits a slow TTY-like signal into 31.5 Hz of bandwidth).