RHF said.....
With the phase-in implementation of DRM, wouldn't a 10 kHz, 20 kHz
or even 25 kHz be a more acceptable and practical 'channel' Spacing
to reduce interference from any 'adjacent' Channels

If DRM was in section of its own in each SW band, rather than amongst
existing AM transmissions, that begs another question. With the
current 5kHz spacing, what is the impact of adjacent DRM
transmissions? As we know, a DRM broadcast on, say, 6005kHz can kill
an AM broadcast at 6010kHz. But if 6010kHz is a DRM broadcast too, to
what extent can error correction come into saving both broadcasts? If
two strong, adjacent DRM signals can withstand each other's spill-over
where two strong adjacent AM signals would usually knock each other
out, then that can only be another advantage of DRM.

Frank Dresser said....
Why reduce the AM shortwave broadcast band at all? The AM SW BC
bands have
been expanded since the SW commercial utility stations have mostly
left.
Just let some of the new expansions go to DRM.

I was in bandwagon jumping mode, assuming that eventually there will
be no AM broadcasting on SW at all (with or without DRM taking the
space). I did say elsewhere that I don't believe AM and FM broadcast
will die completely at all, but if DRM *does* take off, *is*
implemented well enough and *is* embraced by the consumer eventually,
what would be the advantage of continuing AM broadcasts on SW for the
broadcaster? (I realise there are a good few conditions to meet just
there; many "ifs" and "maybes").

Frank Dresser said....
Maybe a station is equipped and licensed to operate on a certain
frequency,
so that's where they operate, DRM or AM. The real, logical reason
might be
that nobody though much about interference until now, and the
implementation
is haphazard.

Well thats exactly what's happened, and I'm sure thats what you're
saying. And if it's not sorted out soon, there will be no chance of
anyone taking DRM seriously and it will be dead before it has even
taken it's first steps.

John S said....
The key to it's success will be whether users will buy the needed
digital receiver. Given that most major brodcasters are moving
toward
satellite, FM and MW broadcasts I don't think there wil be much
reason
for a broad range of SW listerners to buy a digital unit. Neat idea,
but too late.

Possibly. But as I said before, the move away from shortwave is
simply because of what alternatives there are. Listeners generally
want good quality audio, and this is rare with AM shortwave. But look
at the limitations with the media you have listed above. Satellite:
lack of portability, and issues with successful reception (satellite
dishes don't tend to work as well indoors as telescopic antennae do
for SW) although I realise XM, Sirius etc don't have these issues. FM
and MW: portable, and very cheap (at least for the listeners) but the
broadcasters then desert the many listeners who live outside the range
of such transmitters.

On the whole, I selfishly would like to see DRM fall flat on it's arse
if it was to impact on AM broadcasting on SW (this is where Frank
Dressers point of expanding the band for DRM, and leaving the AM
broadcasting parts intact, would be very good) as I enjoy DXing the SW
bands. However, from an international broadcasting point of view I
can see the potential not least in preserving the world of
international broadcasting on SW but also improving the services that
listeners get from it.

Realistically, I think it's already too late. Implementation of a new
technology such as DRM has to be faultless right from start, if only
to ascertain consumer confidence in the technology. If the likes of
Sirius, XM, and Worldspace didn't exist then DRM might seem a more
attractive option than it does now.

With each year that passes, DRM's chances slip further and further
away as other technologies surpass themselves.

Steve, Reading, UK.