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by alfla
3105 days ago
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Ok, great answer. I live in Norway btw. Both the constructive interference and reduced number of transmitter arguments sound reasonable. I'm a bit more skeptical to the power cost, how much more expensive can that really be for FM? Electric power is pretty cheap. Does not really matter what the answer to this is though, given the other arguments. At the moment I have to say I'm not very impressed with the coverage and quality of DAB in Norway, in my opinion it seems worse than FM. But I'm guessing this will only get better over time. My main issue with the adoption is the requirement to buy new receivers, it's just so much waste. The adapters they sell for cars are in general just so ugly and a technically inelegant solution (local FM broadcasting, pretty ironic). A funny anecdote I read in the news was that some of these adapters come with a bluetooth handsfree solution, which also gets broadcast locally on FM. This means that other people driving close to you can listen in on your conversations if you use that functionality. |
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Agreed - DAB coverage is seemingly much more spotty than what is claimed by Norkring (the operator) - makes you wonder what models (or antennas, in the case of field tests) they use to produce the maps.
Add to this the annoying property that whereas a FM signal degrades gracefully - as the signal gets poorer, you simply get more hiss, but can still make out what is being said, DAB basically drops off a cliff - it is fine until it - well, isn't, at which point it is pretty much unlistenable.
As for power, there are two factors both tipping in DAB's favour - first of all, you get good area coverage with lots of channels from one transmitter, seeing as the different stations are interleaved in one stream - say, a dozen channels for a realistic example. Having that same dozen channels on FM covering the same area, you'd need a dozen transmitters, all illuminating the same area.
Additionally, an FM tuner requires a signal which is significantly stronger if it is to decode it properly than what a DAB receiver does.
(This benefit is somewhat offset, power-bill wise, by the fact that DAB final amplifiers must be very, very linear in operation (because of the number of carriers) whereas an FM amplifier need not bother about linearity at all - and, hence, can be run at higher efficiency.)
(For a very rough comparison - the DAB transmitter on Tryvannshøgda providing local radio to Oslo boasts less than 5kW output. The Radio Norge FM site next to it? 88kW.