All posts by Michael Rogers
Below are all of Michael Rogers's postings, with the most recent are at the bottom of the page.
It is empirical and reproducible that moving the telescopic aerial of an FM or DAB radio can result in degradation of the signal quality. The general coverage prediction implies that there is a locally receivable signal, but factors immediate to the receive aerial, topography, buildings and obstructions being passed, house
attentuation, reflections etc, determine whether at a given dx/dt moment the signal is of sufficient quality to be demodulated or decoded. This is more significant at the higher frequencies of DAB. Ergo : unless the field strength is substantial enough to override immediate physical factors, reception quality of DAB and, to a lesser degree of FM, will be variable. Brian, you referred to reception quality maps, could you post links, please. Such would presumably include local topography and structure factors and be more detailed than the large-scale coverage maps.
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Listeners whose DAB service is below par DO consider the benefits it brings. They are just waiting for them to arrive. If they do before FM disappears, fine. If for budget and commercial reasons they dont (as with the DTT COM muxes), a new definition of "benefits" will doubtless emerge. DAB only has to be nearly-as-good as FM in terms of choice and coverage for satisfactory portable and mobile reception. Hope springeth eternal...
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Jonathon : I have the same problem. On FM I get one commercial station (Heart), but not BBC regional; on DAB only Wales - if I jiggle the telescopic aerial and dont move around. I share the concern that budget and profit will determine who gets what in the end. There will be no new investment in FM, so we can but hope for DAB. Major population centres and motorway routes will probably be fine on DAB when all the transmitters are operational. It is the rest of us who may not be content with the upshot...
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Brian, your OBE must be getting ever closer.
So many people appear convinced that you personally control programme content and distribution, muxes, tx masts, propagation, rain-ingress, receiver glitches etc :-)
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Wasnt there something about "free movement of goods AND SERVICES" in those glorious treaties?
There must be secret appendices containing
copyright dogma and exclusions to protect big profits ...
An OBE for Karen Murphy!
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M
New features for "My Settings" box and the "Newsbucket" | BlogsThursday 17 February 2011 9:33AM
Ilfracombe
Yet another enhancement, Brian! Very useful.
Insignificant comment : Kilvey Hill still doesnt show on my map, although one of the strongest signals - on a ground-floor indoor aerial.
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One good U-turn deserves another. It looks as if more flexibility will be forthcoming. Perhaps pragmatism will deliver DAB in major population areas and along motorway corridors - and continued FM for the rest of us.
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Useful update, Brian. Thanks. Query : is there a fixed correlation between frequency and FreeSat channel numbers? My FreeSat receivers only display frequencies.
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Wednesday 2 February 2011 9:32AM
Quality, integrity : Moving the telescopic aerial on my DAB receiver just slightly affects signal strength and/or quality rather drastically. It is far more temperamental than FM at half the frequency. I would be interested in signal quality maps to compare theory with practice. The coverage maps I have seen are basically predicted field-strength maps, so if better maps are available, I would be most interested in any links. Accidented topography is likewise even less DAB-friendly than it is FM-friendly, all the more so on the move. I cannot see DRM+ implemented anytime soon, but the extensive research and trials do indicate it is considered a serious future contender.