Frank Dresser wrote:

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



[snip]


Quite a lot of shortwave station broadcast at more then one frequency at
a time so it possible to have a radio tuned to two frequencies at the
same time and let the radio "interleave" the signals from two sources
when one of the has a drop-out.

(DRM includes "alternative frequency" information, so the receiver is
able to find out these additional signals by itself).

That's diversity reception.

Do a Google on diversity reception.

dxAce
Michigan
USA

Frank Dresser wrote:

"Kristoff Bonne" wrote in message
...



Come to think of it. Why use different frequencies? DRM is able to
handle SFNs (single frequency networks)!

If you would broadcast your signal from (say) two or three different
transmittor-sites, if fading causes one of the signals to drop away, the
signal from the other site(s) will continue to be received.

It would be interesting to see how much power you would need from these
three transmittors together compaired to how much is needed if you only
use a single transmittor.


In the VHF-range, single-frequency networks allow for lower
transmission-power.
(due to the fact that the radio-signal is broadcast from multiple
points, a receiver will receive radio-signals from different directions
so there is more change of a signal coming in with a good quality).

It would be interesting to know if the same thing applies for HF!



Cheerio! Kr. BBonne.

It's worth remembering all the commercial SW data and phone links which were
in use before the satellite era. They had diversity reception,
sophisticated (for the time) digital modes, high power transmitters, high
gain antennas, etc. Yet they abandoned their large investment in SW as
satellites became available. Even with all their technology, SW still
wasn't reliable enough.

I think the average person expects at least the same order of reliablity
from their radios.

One thing is certain, and that is if one is a radio hobbyist DRM is not your
friend. DRM = QRM.

Bearing that in mind, anyone who touts DRM is not your friend. They are your
enemy.

Die DRM, die.

dxAce
Michigan
USA

Diversity reception,huh,what?
cuhulin

And anybody who touts ccrane and Sangean and Tiny Tennas too.
cuhulin

Smokey Yunick once put up a wind generator at his garage shop.The city
of Daytona Beach made him take it down.About a week ago when I went to
the Celticfest Mississippi thingy at the Agricultural and Farm museum
thingy,I saw a wind generator on a tall steel tower,I took a picture of
it too.Yeah,you put up a wind generator on your property and watch your
neighbors start raseing h..l and the stinking city make you take it
down.
cuhulin

Frank Dresser wrote:

Why change? Because:

"DRM can be used for a range of audio content, including multi-lingual
speech and music."

http://drm.org/system/technicalaspect.php

Just try that with some old-fashioned analog system.


When I tune around the shortwave bands, I hear speech of many
languages. And music.


"There is a global trend towards the adoption of digital technology in radio
and communications, especially for distribution and transmission. "

And:

"However, the limited fidelity of existing AM services is causinglisteners
to search for other alternatives."

http://drm.org/system/whydigital.php


Anyone who so much as picks up an AM radio is after something other
than audio fidelity. That's the nature of the beast, and everyone knows
it.


Well, I'm confused on this point. Didn't AM became obselete in the forties
with the introduction of FM? If I remember my history correctly, didn't all
the limited fidelity AM stations go bankrupt as all their listeners were
drawn to high fidelity FM?

It seems limited fidelity AM is in for it again:

"DRM is the only universal, non-proprietary digital AM radio system with
near-FM quality sound available to markets worldwide."


There ya have it. DRM has both "near-FM quality sound" and digital
trendiness.

I can't think of any better reasons for the listener to care.

Frank Dresser

These are the things that SW listeners care least about. If this is the
primary appeal of DRM, it is thoroughly and completely doomed.

Steve

Rumor has it the people behind DRM are working on a new technology that
will bring back the typewriter. This new technology will allegedly turn
a typewriter into a 'near PC quality' word processor.

I own a few very old typewriters,Underwoods mostly.Those newer kind of
typeriters you see at the thriftstores for a few dollars,you can sell
them to Mexico and other third world countries,they still use them.
cuhulin

In article ,
Kristoff Bonne wrote:

Gegroet,


Telamon schreef:
For One and All, ABOUT - Digital Radio Mondiale (DRM) DRM =
http://www.drm.org/.

ALL you need to know is that the implementation was screwed up and
over hyped. OH YEAH and it was lied about a lot buy the DRM
organization. AND it takes up more bandwidth than it was supposed
too. BUT it is just another system than the current analog with its
mixed bag of pluses and minuses, which make it no better than the
current analog system so why change to it?

Aren't you mixing up DRM with IBOC-AM?

Nope. I'm talking about Deception Radio Mondiale.

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.

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?

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.

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.

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

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

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.

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

c. No LW broadcast in NA but I find that MW and SW are quite acceptable.

(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.

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?

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.

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.

--
Telamon
Ventura, California

Why do you think DRM ultimately failed? I think it was simply an idea
that was behind its time, meaning it would have been successful 50
years ago, but is an anachronism today. It's neat that there are still
some DRM broadcasts around, but don't count on that to continue. In
particular, don't sink a lot of money into a DRM-capable receiver.

Steve