wrote in message
...

"Meyer Gottesman" wrote in message
...
The "Radio Crazy" is baaaaakkk!

Sadly the "Radio Crazy" predicts that AM IBOC will be
a total "bust" going the way of the horse and buggy,
the shaving cup, Quad FM(circa 1973).

You heard it first here!


IBOC blows!

Actrually, the AM IBOC sounds far better than analog IBOC, even the kind of
analog you could get on an older receiver and pre-NRSC. FM IBOC is a degree
better than analog FM. The real issue is with occupied bandwidth, not the
quality of the audio.

It's NAB's answer to satellite radio. IT AINT GOING TO WORK. XM
& Siruis are kicking your ass with local weather and traffic offerings.

Not really. Arbitron measures Sirius and XM in local markets if it is
mentioned. In LA, it shows up in less than a dozen diaries out of 7,000.

As Rich says, there are 2.300,000 subscribers. Given what we know about
radio usage, less than 10% are going to be listening at any one time, and
that divided among over 100 channels. That means, maybe 200,000 AQH
listeners, or 2,000 per channel at any one time. The #5 station in Traverse
City, Michigan has more listeners.

So
called "FREE" radio is exactly what you get for your money.

Which, is, in fact, its biggest advantage. Couple that with the existence of
about 700,000,000 "free" radios in the US vs. 2 million for XM and you get
an idea.

For the narrowminded broadcasters I guess Satellite radio is a fad, yes
sportsfans a "Fad"..just like satellite TV,just like cd's and DVD's.Just
like microwave ovens.

It is not a fad. It is a niche. A certain percentage will sign up, and it
will be profitable and successful.

CBS/Infinity/Viacom has it's head squarely up it's ass.

Rich answered this. They are ignoring streaming and satellite as one is not
profitable and the other is too niche.

At least
Clearchannel has the smarts to get involved in satellite delivery, Mel
Karmazin was a complete joke!

CLear Channel has, now, less than 2% of XM. And has stopped providing
programming.

turning his back on the newest form of
broadcasting,AND forbidding streaming audio from ANY CBS stations.

It does not make money, and does not create local market listening.

On 11 Jul 2004 15:04:48 GMT, "David Eduardo"
wrote:


Actrually, the AM IBOC sounds far better than analog IBOC, even the kind of
analog you could get on an older receiver and pre-NRSC. FM IBOC is a degree
better than analog FM. The real issue is with occupied bandwidth, not the
quality of the audio.

I'm afraid I have to disagree. The most charitable spin I can put on
AM IBOC is that it sounds bad in a different way than analog AM sounds
bad, and to my ears, the analog is preferable. The damage IBOC does
to the analog signal is serious and quite noticeable on anything but
the very worst-quality receivers, the interference products have the
potential to do great damage to other stations, and IMHO it's a step
backward for the sake of selling equipment.

As for FM IBOC, yes, the digital signal does sound better than a badly
processed analog signal. It is a shade worse than a
properly-processed analog signal. I produce a weekly program for a
public radio station that is delivered as a 320kbps .mp3 file. That's
lower quality than analog or "CD quality," and FM IBOC is worse yet.
I will concede that to the typical non-audiophile listener, the
difference is not noticeable without a direct A-B comparison.

However, there is an adjacent channel interference issue with FM as
well, so the question arises, why are we junking up the band and
reducing everyone's effective coverage area for something that is,
looked at in the most positive possible light, just "not worse" than
what we have? Just to be "digital?" Most listeners think they
already have digital radios, anyway. (They show digits for frequency,
don't they?)

I do not understand this at all, except that a few big corporations
with a lot of lobbying clout stand to profit from it, if it becomes
widely accepted.

Mark Howell

Mark Howell had written:
| On 11 Jul 2004 15:04:48 GMT, "David Eduardo"
| wrote:
|
|
| Actrually, the AM IBOC sounds far better than analog IBOC, even the kind of
| analog you could get on an older receiver and pre-NRSC. FM IBOC is a degree
| better than analog FM. The real issue is with occupied bandwidth, not the
| quality of the audio.
|
| I'm afraid I have to disagree. The most charitable spin I can put on
| AM IBOC is that it sounds bad in a different way than analog AM sounds
| bad, and to my ears, the analog is preferable. The damage IBOC does
| to the analog signal is serious and quite noticeable on anything but
| the very worst-quality receivers, the interference products have the
| potential to do great damage to other stations

Simple question:
If AM IBOC is such hot stuff, why is it restricted to daytime hours only?

I can now hear the damage it does to the analog signal on KCBS. The
effect varies from radio to radio, but on almost all of them, the
noise floor goes up when IBOC is on.

On a synchronous detector, it sounds worse...like a mosquito buzzing
in the background. That's true even in a regional park with no power
lines or people nearby. And, on my AM stereo radios with those detectors,
that's with the stereo decoder OFF.

What's next: analog radios with 2 kHz bandwidth so we don't hear the
buzzing noise placed there to serve receivers that don't exist?!?!?

| However, there is an adjacent channel interference issue with FM as
| well, so the question arises, why are we junking up the band and
| reducing everyone's effective coverage area for something that is,
| looked at in the most positive possible light, just "not worse" than
| what we have? Just to be "digital?"

I suspect this is the back door through which DRM will slip for
broadcast radio.


--
Mark Roberts |"Bush campaign ads boast that 1.5 million jobs were added in the
Oakland, Cal.| last 10 months, as if that were a remarkable achievement. It
NO HTML MAIL | isn't. During the Clinton years, the economy added 236,000 jobs
in an average month." -- Paul Krugman, NY Times, 7-6-2004

In article ,
Mark Roberts wrote:

On a synchronous detector, it sounds worse...like a mosquito buzzing
in the background.

That's because it's in quadrature, which is "invisible" (modulo
transmission artifacts and channel noise) to envelope detectors. Your
sync. detector is only detecting one sideband at a time, so the IBOC
carriers don't cancel out.

(This is why I no longer listen to WBZ much during the daytime.)

None of the engineers I've talked to like the AM system. Some of them
see it as having potential to bring back a long-lost audience, in
spite of its significant flaws. Most of them see it as a pointless
corporate mandate that will waste their engineering budgets, reduce
their coverage areas, and dirty up their audio chains.

People I talk to in *my* business (computing, not broadcasting) are of
the opinion that traditional, reserved-spectrum broadcasting will
cease to exist inside of three decades, for various reasons, social as
well as technological. (That's assuming it isn't already dead -- many
of the people I know, my age and younger, are simply no longer users
of radio at all. It doesn't connect with them in any meaningful way,
nor does it serve their needs.)

-GAWollman

--
Garrett A. Wollman | As the Constitution endures, persons in every
| generation can invoke its principles in their own
Opinions not those of| search for greater freedom.
MIT, LCS, CRS, or NSA| - A. Kennedy, Lawrence v. Texas, 539 U.S. ___ (2003)

On 13 Jul 2004 04:34:38 GMT, Garrett Wollman ("Garrett") writes:
Garrett People I talk to in *my* business (computing, not broadcasting)
Garrett are of the opinion that traditional, reserved-spectrum broadcasting
Garrett will cease to exist inside of three decades, for various reasons,
Garrett social as well as technological. (That's assuming it isn't already
Garrett dead -- many of the people I know, my age and younger, are simply
Garrett no longer users of radio at all. It doesn't connect with them in
Garrett any meaningful way, nor does it serve their needs.)

Specifically, your "business" is computer systems support at
a techie university, so I am guessing that the people you're
referring to are students? (If that's not the kind of people
you're talking about, could you describe who you mean?)

Most of the people I know at MIT don't to any AM radio, but they
may listen to a few NPR shows. Entertainment is mostly not from
the radio: music is on portable media or file-sharing networks.
But MIT students (in my few decades of experience with them) are
particularly un-representative of popular culture or societal norms.
I think you would find that the people of the same age across the
river at BU to have somewhat different behaviours. When you say
that it "no longer" servers their needs, I think maybe you're just
suggesting that they now live on campus or in the tiny walking city
(with demographics unlike anywhere else in the country, anyway),
they don't like talk radio, don't drive cars, and are very busy studying.
I would not base a prediction of whether people will be interested
in broadcasting on the behaviour of MIT students, because they've
never been very interested in popular commercial broadcasting,
as it has never really served the needs of the uber-nerd subculture.

What shows do you listen to while driving in your car,
and what do you do for traffic reports, and how do you
get your local news and weather on video or while driving?

But I would be interested in hearing technical and societal arguments
about how traditional broadcasting won't be interesting or viable in
the near future, or even in 30 years. (2035 is a long ways off, and
I think there could be major technological changes by that time which
could affect how broadcasting works.)

In article , says...


In article ,
Mark Roberts wrote:

On a synchronous detector, it sounds worse...like a mosquito buzzing
in the background.

That's because it's in quadrature, which is "invisible" (modulo
transmission artifacts and channel noise) to envelope detectors. Your
sync. detector is only detecting one sideband at a time, so the IBOC
carriers don't cancel out.

You have this exactly wrong. Envelope detectors are not sensitive to
the phase of the carrier, responding instead to the square root of the sum
of the squares of the I and Q components of the modulation:

SQRT(I^2 + Q^2)

(The carrier must be present in order to properly bias the envelope
detector, but, upon demodulation, the carrier simply appears as a DC term.)

A synchronous detector will detect either the I channel or the Q channel (or
some linear sum of the two) depending on the phase of the regenerated
carrier. It can be configured to reject the Q channel entirely by ensuring
that the regenerated carrier is precisely in-phase with the original
carrier.

To detect single sideband, you need two synchronous detectors whose carrier
inputs are in quadrature and whose IF inputs are also in quadrature. A
single synchronous detector will _not_ detect single-sideband.

See any textbook on modulation theory.

Mark Roberts wrote:

If AM IBOC is such hot stuff, why is it restricted to daytime hours only?

Because the group delay that is the result of the uneven ionosphere prevents
it from being decoded properly when the signal is received on skip, and the
amount of stuff coming over the horizon on skip prevents it from being
properly received when it's being received on groundwave at night.

I can now hear the damage it does to the analog signal on KCBS. The
effect varies from radio to radio, but on almost all of them, the
noise floor goes up when IBOC is on.

I wouldn't be bothered by this so much if the digital system actually
sounded good. But the audio quality of the digital carrier is actually
a lot worse than good analogue AM. It's like listening to Cylon Warriors.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey had written:
| Mark Roberts wrote:
|
| If AM IBOC is such hot stuff, why is it restricted to daytime hours only?
|
| Because the group delay that is the result of the uneven ionosphere prevents
| it from being decoded properly when the signal is received on skip, and the
| amount of stuff coming over the horizon on skip prevents it from being
| properly received when it's being received on groundwave at night.

I didn't quite expect an answer to a rhetorical question -- but it does
point to a very fundamental flaw in the scheme.


--
Mark Roberts |"Bush campaign ads boast that 1.5 million jobs were added in the
Oakland, Cal.| last 10 months, as if that were a remarkable achievement. It
NO HTML MAIL | isn't. During the Clinton years, the economy added 236,000 jobs
in an average month." -- Paul Krugman, NY Times, 7-6-2004

In article ,
Mark Roberts wrote:
Scott Dorsey had written:
| Mark Roberts wrote:
|
| If AM IBOC is such hot stuff, why is it restricted to daytime hours only?
|
| Because the group delay that is the result of the uneven ionosphere prevents
| it from being decoded properly when the signal is received on skip, and the
| amount of stuff coming over the horizon on skip prevents it from being
| properly received when it's being received on groundwave at night.

I didn't quite expect an answer to a rhetorical question -- but it does
point to a very fundamental flaw in the scheme.

Sorry, I can't seem to find Bob Orban's reply to this. But I agree with
Bob that the encoding scheme is very robust about dealing with group delay
issues. Even so, I have found the actual skip performance poor to the
point of unusability.

Bob, do you have a citation on any actual measurements of this stuff?
Ionosonde data is easy to get, so it should be really easy to build a
simulation of ionospheric distortions in matlab or something, even if you
just take into account group delay and multiple reflections. Has anyone
actually done any simulations on the current encoder to see how it survives
under various simulated skip conditions? I'd be curious to see which of
the various skip characteristics is the most serious issue.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article , says...


Mark Roberts wrote:

If AM IBOC is such hot stuff, why is it restricted to daytime hours only?

Because the group delay that is the result of the uneven ionosphere prevents
it from being decoded properly when the signal is received on skip, and the
amount of stuff coming over the horizon on skip prevents it from being
properly received when it's being received on groundwave at night.


I do not believe that this is correct. The modulation scheme of iBiquity's
IBOC system is basically multiple carrier COFDM, and is quite similar to the
modulation scheme used in Digital Radio Mondiale (DRM), which is known to be
robust in the face of selective fading. It all depends on the symbol spacing
used in the COFDM carriers. If the multipath period is shorter than the
symbol spacing, then the various reflections will reinforce. Because there
are multiple narrowband carriers in COFDM, the data rate on each carrier can
be very low (allowing long symbol spacing), yet the presence of multiple
carriers still allows the overall system to deliver a high data rate.