| Hi, 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. |
DAB has obviously arrived and is here to stay in Norway, but I'm interested to see what the rest of the world does. My guess is that internet connected vehicles will be a both cheaper and better solution for consumers in many regions. Given the amount of data people use on their phones today, it seems likely to me that providing audio streaming of DAB equivalent bandwidth is feasible - even in Norway.