In article ,
Kristoff Bonne wrote:

Gegroet,


Oeps. I am a bit behind scedule replying to this one.

No problem.

Telamon schreef:
Nope. I'm talking about Deception Radio Mondiale.
Didn't know this one. :-)

Nice!!!

You know why it's nice? Because it true.

DRM might bring people back to LW/MW/SW and they might not even know
it.
LW and MW are around 24/7 but SW stations change frequencies all
the time. It takes a little more effort to find a SW station.

That's what "AF" is for. (Alternative Frequency information inserted
into the DRM stream, just like on FM/RDS).

The problem is that you have to get a decent signal to get the
information.

One of the things with DRM (and especially with the DAB/DRM chipset
now available) is that the user will just be presented with a list of
stations and he will just have to pick the one from the list. She
will not know if she is listening to a DAB broadcast at 1.4 Ghz or
long-wave at below 200 Khz.

Most women are clueless about technology but what about us guys?

Great. Do I write "she" to say "hey, let's not be sexist and say that
only men know about technology and radio", and you reply "women don't
know anything about radio".
:-)

You could have written the same thing without he or she. Why bring sex
into it.

But seriously what station is going to broadcast the whole SW station
schedule in the background data stream. Do you have any idea how big
that is? You would need to do this because schedules (times and
frequencies) change all the time.

First of all, that's not such a big issue, as there do exist things like
the "EPG". It broadcasting-technology neutral so it can be used in
DAB, DVB and DRM.

What is "EPG"? If it's another digital stream then you have to able to
pick up the signal to get the information and that is a lot of
information for a low bit rate signal that can, lets face it, have drop
outs.

Second, the only thing the radio will do is scan all frequencies it can
receive and compose a list based on that. That's how DAB radios work
nowdays too.

I can do that right now so who needs DRM?

DRM has two major advantages: - it does away with fading, which is
one of the things people find most annoying about LW/MW/SW. The
"audio-quality" aspect is a bit mood as it all depends on what mode
you are using and I think for most people is not the most important
element. But if you produce a stable signal without fading, this
would make LW/MW/SW broadcasts quite acceptable by most people.

1. Fading
a. Fading is replaced with dropouts. I fail to understand how that can
even be considered an improvement.
Only if the signal goes below a certain S/N threshold.

Which it will.

b. I don't find it the most annoying thing.

Well, last year I was in Northern Italy and I was listening to the
worldservice of the public broadcaster of Flanders (dutch-speaking
belgium) on shortwave; and -to be honest- my wife was pretty anoyed by
the fading-element.


Somebody who just "hears" a radio (so, who is not really "listening") is
used to have a radio with a more-or-less constant quality-signal. They
are not really used to have a radio sound good, then get all kind of
noice, then sound good again, and then with noice again.

It attacks their attention and this annoys them. Radio should be a
"background noice" thing and this means that is should be more-or-less
constant.

It looks to me that you have not used a good analog radio with sync
detection and an adjustable AGC. With those two functions at your
disposal you won't have that problem.

c. Analog has sync detection, which eliminates most of the fading most
of the time. This is much better than drop outs.


AFAIK, sync detection is against partial-cochannel interference, not
against fading.

This tells me that you have never used a radio with sync detection. A
sync detector helps with selective fading and a good one will give weak
signals a boost. This together with a properly adjusted AGC will give
you constant quality audio.

2. Audio quality.
a. I have several analog radios that during real SW reception sound much
better than the audio demonstration files on the DRM website.

True, but there are stations who also sound worse.

So what that got to do with it. The DRM "sound" sucks with a good signal
and analog station with a good signal sounds much better. A DRM signal
that was weak would be dropping out and would get turned off.

b. An analog radio with sync detection would sound better than a DRM
radio using the same radio spectrum bandwidth.

Do you actually have a DRM-radio? Can you compair?

No I don't. I told you I listened to the samples on the DRM website and
besides that there are plenty of examples on the web of low bit rate
audio encoded files that don't sound very good.

c. No LW broadcast in NA ...
Correct, but I read somewhere that Australia is thinking of restarting
broadcasts on LW (because of DRM).

Most NDBs have disappeared from that band overthere.


... but I find that MW and SW are quite acceptable.
Are there domestic SW-broadcasts in the NA? CBC/RC?

Yes there are quite a few SW broadcasters and broadcast sites in NA but
I spend little time listening to them.

(The term "near-FM" is marketing talk, just ignore it).

No I won't ignore it. The better sound quality hype is just another
example of the sales deception that surrounds the DRM technology.

No, I meant that the term "near FM" is just marketing-talk. It allows
for better audio then AM, that is for sure but it all depends on what
mode you use.

I know what you meant. You are missing my point that this is not the
extent of the hype and I strongly disagree that DRM sounds better than
analog AM. It clearly sounds worse. You would have to increase the
bandwidth DRM currently uses for it to sound better.

If you listen to a very-low bitrate auxilairy channel (e.g. one used for
broadcasting traffic-messages) it will sound much worse then FM.
If you use it in the 20 KHz mode in the 11 meter broadcasting-band, it
will probably sound better then FM.

And just how do you think analog would sound using the same bandwidth?

The audio-quality-issue is technically much more complex then this, but
-marketing-wize- "near FM" is probably the simplest thing to say.


It allows broadcasters to break into certain markets by broadcasting
from abroad. BCE (RTL's broadcasting arm) plan to use it to broadcast
using DRM on LW, MW and SW towards different countries.

I don't know about this. What exactly does the DRM technology have to do
with enabling markets?

It allows them to broadcast with a "accepable" signal across the borders
so that -using their Luxembourg license- they can "break into" other
markets.

So your argument for DRM here is change the technology to overcome a
political problem?

The new frequencies on LW and MW they have requested at the ITU are
279 Khz (Junglinster towards Germany), 567 Khz (Clervoux towards the
Netherlands), 783 Khz (Beidweiler towards France) and 1098 Khz
(Clervoux towards Belgium).

I'm happy this is not in my part of the world.

Why not. The more channels, the better.

Just the opposite. One low bit rate crappie sounding DRM signal wastes
three channels. A good sounding DRM signal would waste twice as many.

Anycase, the biggest user of DRM will probably be not in Europe, but
will be in China. (for a very different reason, but that's a different
discussion).

Actually besides sounding like crap DRM biggest problem is that
broadcasters can start controlling who can listen. DRM would also be
easier to jam. Small wonder China would go for it.

For SW, they have asked the HFCC for coordination for two
frequencies: 5990 and 6095 Khz.
I would prefer that the DRM transmissions stay out of the international
broadcast bands and stick to the digital utility frequencies.

Why is that. If they are general-public broadcasts, that's where they
belong, isn't it?

No they are a digital mode that interferes with the analog signals I
want to listen too. They should stick to the part of the spectrum for
digital mode signals.

What does a x. KW high-power general-public broadcasting-station do in
the same band as medium-power utility-broadcasts?

Why should a digital mode signal be sitting in the middle of a analog AM
broadcast band?

If these broadcasts are analog or digital are IMHO of no importance.

I don't know why you would say this. Usage and mode of transmission
determine what frequency you transmit on. Why should DRM be an exception?

Cheerio! Kr. Bonne.

Yeah, cheerio to you too.

--
Telamon
Ventura, California