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Old 26th Jun 2022, 6:35 am   #25
Radio Wrangler
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Join Date: Mar 2012
Location: Fife, Scotland, UK.
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Default Re: Threads getting more modern?

Ah, what you're seeing there is analogue stuff (genuinely random noise) getting into someone's attempt at a nice, clean digital waveform. However hard you try, there is always noise. All clocks have jitter because oscillators are noise-based machines. Right down at the particle physics level, quantum mechanics throws random uncertainty into the mix. You just can't make nice Boolean digital things, the analogue world corrupts them. What you can do is get close enough that you can live with the remaining uncertainty.

Eureka147 was the project which developed DAB. They got two big things wrong. They underestimated progress in microelectronics, that soon improved processors would have allowed them to do a better system, and we are having to live with their compromise. They tried to make a system that would work for all purposes. They tried to keep processing demands down to help battery life in portables, so that you could get at least a few hours listening on a set of batteries.

The nature of the deployment of such a system means that we're stuck with it for at least a few decades. Battery consumption still hasn't been made competitive with a basic old-school FM receiver. Even at the highest data rate options and a clear channel over a short distance, the choices of bit depth, compression and data-rate prevent it being competitive with a good FM receiver within the service range of a transmitter. What Eureka147 has delivered is lots more channels, though many are in the heavily compressed low rent district.

A less obvious effect is that transmission is as a number of multiplexes, each carrying a large number of 'stations'. If you want to transmit your station on DAB, you have to do a deal with the infrastructure operators for a slot on their multiplex. You can no longer get a licence and run your own transmitter. This also means there is likely to be no empty space to sneak a pantry transmitter in.

DAB is already obsolescent, it has been for some time. Radio services over internet are scaleable, different data rates are easily offered and the end user can download new software to handle new formats as they arise. Internet access is becoming mobile with data rates targeted ar movie-watching and fast game-play.

Maybe the frequency space of some multiplexes will become vacant and a pantry transmitter becomes viable for someone to demonstrate radios from this period? However, there is now a lot of DAB radios in cars, where most radio listening happens, and they are built in. This adds a lot of inertia opposing change. But change is inevitable, eventually.

Joe, digital stuff can be done very well, better than the limitations on analogue stuff, but that doesn't mean that it has been done that well. Decisions and choices early on often set the bar disappointingly low... usually for the profit motive.

Cheap and nasty has always beaten the good stuff in terms of both fame and fortune. The public are aware of Clive Sinclair and Alan Sugar. Few have heard of Peter Walker and Arthur Radford.

David
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