Phil Cook wrote:
Ad C wrote:

Satellite wipes the floor with DAB.

FM wipes the floor of them both.

In theory. Come to the rougher bits of London or Birmingham and you
will get fzzz tzzz kssskz from pirates ruining your reception.


That's unfortunate, but that only applies to a small fraction of the
population and it certainly does not excuse the fact that the audio
quality on DAB has been degraded to a level that is significantly lower
than FM with good reception. Remember that a large majority of people (I
can't prove that, so don't ask me to, but I'm very confident that I'm
right) get pretty good FM, so why should they have their audio quality
degraded just for the sake of future profits for the commercial radio
groups and to allow the BBC a better chance of renewing their Charter?


--
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spiney wrote:
I've looked at the above links, but sorry, you can't have a portable
digital satellite radio receiver (because it would require its own
satellite dish!).

If it's some sort of portable rf link back to a digibox ("battery
powered videosender"), then ok, that would work, but not enough info is
given to make this clear.

It seems fairly obvious.


Not brilliant, because whatever DAB's drawbacks, it really is portable,
and also has local radio (Sky doesn't).

There's no local radio on DAB in my locality.

There is local radio on satellite in my locality.

Kristoff Bonne wrote:
Gegroet,

spiney schreef:

I've looked at the above links, but sorry, you can't have a portable
digital satellite radio receiver (because it would require its own
satellite dish!).
If it's some sort of portable rf link back to a digibox ("battery
powered videosender"), then ok, that would work, but not enough info is
given to make this clear.


Does it offer some kind of "return-channel" so that you can "control"
the receiver from the kitchen/garden/...?

E.g. can you switch to another radio-station or start or shut down the
receiver at a distance?

Assuming it has a line-out socket it will be quite useful to get stereo
sound on a remote TV connected to the sky box via RF....

spiney wrote:

Not brilliant, because whatever DAB's drawbacks, it really is portable,
and also has local radio (Sky doesn't).

Unless you include most of London's local stations, plus a few large regional
commercial stations, and (if you define them as such) the BBC's five 'Celtic'
radio services, Wales, Cymru, Scotland, Nan Gaidheal, and Ulster.

--
Mark
Please replace invalid and invalid with gmx and net to reply.

Just to pick up on a few things (above) ......

DAB has local stations, depending on where you are, admittedly usually
just independent ones, not BBC local.

XM and Worldspace exist, but are mainly or wholly subscription, and
more like terrestrial networks in coverage (you can't "point at" a
particular satellite). I mentioned shortwave DRM because it's also
quite similar in concept.

I think the Sky description of "digital radio" is extremely misleading,
seeing as it's only a wireless loudspeaker link to an existing digibox,
and the wording is deliberately phrased so as to disguise this (eg,
"compatible with"!).

I also find fm pirate radio highly annoying, eg when trying to listen
to R4 on Walkman, particularly since they often come up right next to
it, with much too big power/deviation, sometimes making the legit
stations unreceivable.
It's quite remarkable that you can be sent to prison for not having a
tv license, yet these pirate stations seem immune to any official
sanctions!

spiney wrote:
Just to pick up on a few things (above) ......

DAB has local stations, depending on where you are, admittedly usually
just independent ones, not BBC local.

XM and Worldspace exist, but are mainly or wholly subscription, and
more like terrestrial networks in coverage (you can't "point at" a
particular satellite).


You're going to struggle picking up XM because it covers the US, not the
UK.


I mentioned shortwave DRM because it's also
quite similar in concept.


It's not transmitted from satellites.


I think the Sky description of "digital radio" is extremely
misleading,


The Sky Gnome allows you to receive digital radio, so what's the
problem?


seeing as it's only a wireless loudspeaker link to an
existing digibox, and the wording is deliberately phrased so as to
disguise this (eg, "compatible with"!).


I bet you're one of these people that object to radio being delivered
via the internet being called radio, and TV delivered via broadband
being called TV?


I also find fm pirate radio highly annoying, eg when trying to listen
to R4 on Walkman, particularly since they often come up right next to
it, with much too big power/deviation, sometimes making the legit
stations unreceivable.


That's unfortunate. But that doesn't justify them degrading the audio
quality on DAB to sub-FM levels.




--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

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to above poster (DAB sounds worse ...).

I never said XM was available outside USA.

Similarly, worldspace is European/Africa only, although with some
regional variations in this case.

DRM is shortwave, which i also said above (!).

The point being that all these systems are similar in type of coverage,
and require subscription.

3Ghz is received on portable radios, but only having tiny antennae, so
the channel capacity is much reduced, there are far fewer stations
(remember, Ku band carries tv and radio simultaneously!).

On the other hand, Ku band sat radio is directional, giving much more
choice, and many of the stations are unencrypted.

I've said what my problem with the Gnome is.

Why on earth would i object to people getting broadcast channels via
the Internet?

You don't like DAB? OK, then, just don't use it.

spiney wrote:
to above poster (DAB sounds worse ...).

I never said XM was available outside USA.

Similarly, worldspace is European/Africa only, although with some
regional variations in this case.


Plus Asia.


DRM is shortwave, which i also said above (!).



But what has that got to do with satellite?


The point being that all these systems are similar in type of
coverage, and require subscription.


So?


3Ghz is received on portable radios, but only having tiny antennae, so
the channel capacity is much reduced,


The channel capacity is lower on the radio systems because they use a
narrower bandwidth. Not because they use tiny antennas (at 3 GHz a
half-wave dipole is only 5 cm long).


there are far fewer stations
(remember, Ku band carries tv and radio simultaneously!).


Yeah, and the bandwidth used is enormous.


On the other hand, Ku band sat radio is directional,


All satellite transmissions are directional because they're transmitted
from a dish, and dishes are inherently directional.


giving much more
choice, and many of the stations are unencrypted.

I've said what my problem with the Gnome is.


But what *is* your problem with the Gnome?


Why on earth would i object to people getting broadcast channels via
the Internet?


Some do object, and given that you object to a receiver of digital radio
being called a digital radio then I thought you'd object to that too.


You don't like DAB? OK, then, just don't use it.


I don't, apart from occasionally listening to check what it sounds like,
and it always sounds utterly ****e.


--
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I can't reply in full to all these rather pedantic quibbles, however
......

Worldstar covers part of Asia, not all of it.

All satellite is not directional, XM isn't for instance.

The way Gnome is advertised is misleading, that's all. Otherwise, I'm
sure it's just what some people want. FIne.

A smaller antenna is inherently worse, as SNR is lower, therefore
channel capacity is reduced, regardeless of other factors (see
Shannon's formula).

spiney wrote:
I can't reply in full to all these rather pedantic quibbles, however
.....

Worldstar covers part of Asia, not all of it.


What were you saying about pedantic quibbles?


All satellite is not directional, XM isn't for instance.


The XM signal WILL BE transmitted from a dish on the spacecraft, and
dishes are ALL directional, therefore XM's signal is directional.


The way Gnome is advertised is misleading, that's all. Otherwise, I'm
sure it's just what some people want. FIne.

A smaller antenna is inherently worse, as SNR is lower, therefore
channel capacity is reduced, regardeless of other factors (see
Shannon's formula).


That's nonsense though, because the field strength for XM is far, far
higher than the field strength for DVB-S signals. And:

C = B log2 (1 + SNR)

C = capacity, B = bandwidth.

Therefore, capacity is directly proportional to bandwidth, but weakly
dependent on SNR.

Basically, the spectral efficiency in bits/s/Hz (capacity / bandwidth)
isn't much different for XM and DVB-S, and it's the bandwidth that is by
far the main reason why DVB-S has such a massive capacity compared to
XM.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

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