"Kristoff Bonne" wrote in message
...
Gegroet,


Frank Dresser schreef:

Yes, but we at rec.radio.shortwave celebrate conspiracy theories and
Hidden
Knowledge. So, would it be impossible to develop a new generation of
IBOC-AM which would have independent programming on the digital
sidebands?

AFAIK, the standards say that -when the signal-quality of the digital
signal drops to low- the radio should switch back to analog.
There seams to have done quite some effort to keep the analog and
digitale signals syncronous.

This means that the analog and digital audio-channels must be the same.
(this of course does not apply to any additional digital channel).

Right. But I'm wondering what the technical limits of the IBOC scheme are.
Are the digital sidebands the same, and, if so, must they remain the same?
I'd assume a current IBOC radio would ignore digital sidebands differently
encoded and fall back into AM mode. So, I'd think independent programming,
even pay programming, isn't out of the question.



From what I understand, IBOC was developed because the US broadcasters
did not like DAB/eureka for a number of reasons; one of them being "it
did not fit the current business model"; so that why they opted for a
system that allowed for as less as possibe new content and where the
digital channel is contenwise the same as the analog channel, only with
better audio-quality; and -therefor- influence the current situation in
the radio-market as less as possible.

The funny thing is that -with nationwide satellite-radio and podcasting-
the radio-market is changing anyway.


Also, when the presumed analog phase-out is completed, will the channels
be
restored to the old standard, or will the broadcasters have to find
something to do with all that redundant bandwidth?

Depends on the legislation. If it has proven to have worked OK for I
don't know how many years (during the switch-over) why go back to the
old bandplan?

That is exactly what I'd expect.


A fully-digital frequeny-slot in band II (400 Khz) does allow for -say-
3 to 4 radio-channels at as-good audioquality as current FM; why go back
to just one channel.
Radio-stations will probably be interested in these new channels to
compete with XM, sirius, podcasting, (perhaps) DVB-H, etc. etc.


Frank Dresser
Cheerio! Kr. Bonne.

I'm looking at the IBOC plans from a radio hobbyist's perspective. DXing is
degraded by the wider channel, especially since it's filled with digital
noise. And I have a hard time believing there's a great unfilled demand for
better sounding AM radios. If there were such a demand, the better radios
which are available right now would be better sellers. But people are happy
buying cheap AM radios with bad sound. I just don't believe that there's
some huge profitable market for better sounding AM radios, even if they work
with some fancy new modulation scheme.

More than that, there's little historical reason to think most people want
better sound. The Hi-Fi AM experiments of the late 30s and 40s didn't
trigger a large demand for great sounding radios. FM foundered from the
late forties to the seventies. AM stereo erupted with great fanfare and is
now almost entirely gone. People are actually trading their good quality
landline phones for Satan's garbley invention, the cellphone.

So, it might seem that the people who are actively promoting IBOC are either
risk-takers, stupid or have a hidden backup plan in the case that "HD radio"
somehow doesn't manage to open up enough wallets.

Frank Dresser