Re: [IRCA] DRM vs IBOC

["Andrea Lawendel" <lawendel@xxxxxxxxx>]

On 3/25/07, Scott Fybush <scott@xxxxxxxxxx> 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
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