On 3/25/07, Scott Fybush <[EMAIL PROTECTED]> wrote: > > > > My pleasure. I'm hoping some of the Europeans who lurk on the list might > chime in with some more detailed observations about how DRM works in > real-world conditions over there.
Pronto. >From a purely (analog) DX oriented POV, Scott, DRM tests on the MW band here are a nuisance. As correctly pointed out DRM was not born hybrid, and since there's still no commercial receivers offering worth of the name, one really wonders how come so many EBU federated broadcasters (there have been some official complaints bringing Croatia to reduce its DRM testing for instance) are putting so much power into a noise nobody is listening to. I've spoken with the "infrastructure" guys at RAI, they have a very nice monitoring center in Monza, close to Milan (and the renowned Formula One track) about their tests on 693. They're telling me how happy they are about DRM efficiency. One of the engineers told me how they can listen and decode to 693 in the daytime, at remarkable distances. It would seem you can actually cover a larger area with less power thanks to DRM. But I must say this picture is quite different from what fellow DXers trying to synch on the same digital signal tell me. RAI's technician usually reply it's their antennas fault. Looks like their reception tests are conducted with one of those pre-release Sangean/Roberts DRM 40 portables, which are equipped with rotating ferrite antennas. "The aerial must be magnetic" is their mantra, "electrical noise destroys DRM". Which is really fun hearing, I must say! It's really difficult to say. On SW DRM has been highly disappointing given its "on/off" nature in a ionospheric propagation environment. Analogue fading still allows you to extract meaning from a transmission, especially if you know your foreign languages well. With DRM it's either very good or very absent, which drives listeners crazy (and they're highly engaged listeners who spend time and money to modify their receivers and set their PC up). They say local tests on 26 MHz are going much better, several public broadcasters and some commercial ones are considering that. But what about DRM on FM? I'm pretty sure DRM+ will be extended up to 120 MHz as told. But testing will be fare more difficult, because FM channels are spaced 100 kHz here (in Italy's total spectral anarchy they're spaced even less!). There's more than the lack-of-receivers factor with DRM. At least in the US people can find a few alternatives in shops. In Europe, a number of public broadcasters has trials in place but it's no real "system": if it weren't for a few tens of engineers at the stations, literally nobody would know about DRM, because *nobody* really care about MW in many European countries. Perhaps only Spain and UK do listen to commercial stations in this band. France, where there's still an audience for LW, MW "renaissance" is a failure with commercial broadcasters after they have been authorized to use frequencies the State owned Radio France has left. Low power stations open and often close down in a few months. Commercial or public, European radio speaks FM. MW band is really dead as far as the listeners are concerned. Reviving that via a digital mode which nobody can tune for lack of hardware is one of these typical European delusions... As for quality, last year I've had the opportunity to take part in a IBOC field test arranged by a commercial FM station in Switzerland. I also spoke with an Italian company trying to tout HD Radio here. I must say Ibiquity quality on FM is far better than DRM AAC audio on SW and MW, but we're talking about much wider spectrum here, so not really surprising. Suddenly, a few days ago a local FM station here in Varese (midway between Milan and Switzerland) announced a test based on FMeXtra and its SCA approach: this is the first in band transmission based on a digital mode. There will be some regulatory problems with SCA on FM here, since use of subsidiary carriers in the FM baseband is limited to 76 kHz by ETSI regulations (FMeXtra goes up to 99 kHz). But the response to these tests is huge, I'm told several stations would be willing to try it for themselves. So that's it. I know the TA MW DXer is speaking here, but I'm fairly convinced that even given that multiple streams/programming thing, there's nothing in DRM or other digital modes which cannot be done with a more efficient use of analogue technologies, better analogue receivers and better spectrum policy. And above all better, more compelling programming. Does Europe want digital radio in a previously analogue band? Well, we'd have to fill our shops with digital receivers and mandate a complete analogue switch off, exactly like we did with terrestrial TV. With DRM, any "transition" phase would mean taking away extant MW or FM bands from broadcasters and listeners. Nobody really wants that. We've been having DAB channels for close to 15 years (15!) in the VHF Band III and outside the UK (and to a far lesser degree Germany, Denmark and now Switzerland) there's not a digital radio market at all. Fifteen years. In 2005 the Italian FCC eventually regulated DAB licensing on the UHF L band (VHF Band III licenses would be a simple fall back option when the L Band be full). You know how many commercial networks applied for a DAB license? Guess it: zero, nilch, nada, nessuna. So much for listeners "convenience". 73s Andy _______________________________________________ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
