Spectrum plot of an IBOC AM station

Spectrum plot of an IBOC AM station

Post by Davi » Thu, 26 Feb 2004 00:42:51

Thanks to Bob Gonsett

http://earthsignals.com/add_CGC/KMXE.PDF

 
 
 

Spectrum plot of an IBOC AM station

Post by Maximu » Thu, 26 Feb 2004 02:31:47


HD=? Looks like if you got too many of these things splattering all over
there would be lousy reception for sure. Not everybody can afford a $3000
receiver that could knock out either.

Il Dolce Far Niente


Quote:> Thanks to Bob Gonsett

> http://earthsignals.com/add_CGC/KMXE.PDF

 
 
 

Spectrum plot of an IBOC AM station

Post by Frank Dresse » Thu, 26 Feb 2004 03:38:05


Quote:> HD=? Looks like if you got too many of these things splattering all
over
> there would be lousy reception for sure. Not everybody can afford a
$3000
> receiver that could knock out either.

> Il Dolce Far Niente

It certainly would be tough to receive adjacent channels.  I don't think
a $3000 radio would help much, because the IBOC sidebands are right on
the adjacent channels.  It would be similiar to trying to receive a
distant station when a local is on the same frequency.  And the local
station never gives it's continual noisy modulation a rest.

I suppose the best way to receive adjacent channels would be nulling the
sideband noise out with the antenna.

Frank Dresser

 
 
 

Spectrum plot of an IBOC AM station

Post by Frank Dresse » Thu, 26 Feb 2004 03:38:17


Quote:> Thanks to Bob Gonsett

> http://earthsignals.com/add_CGC/KMXE.PDF

Thanks for the link.

That spectrum is consistant with what I heard a few evenings ago around
720 kHz.  WGN's engineer said it wasn't them, and I haven't noticed the
noise since then.

Has anyone heard the sidebands produced by IBOC?  The best description I
can come up with is something like "digital white noise".

Frank Dresser

 
 
 

Spectrum plot of an IBOC AM station

Post by Ron Hardi » Thu, 26 Feb 2004 04:15:27


> That spectrum is consistant with what I heard a few evenings ago around
> 720 kHz.  WGN's engineer said it wasn't them, and I haven't noticed the
> noise since then.

> Has anyone heard the sidebands produced by IBOC?  The best description I
> can come up with is something like "digital white noise".

It's just a noise rush, but not white exactly.  The giveaway is that it's on
only one sideband of the station you're trying to hear.  If you hear it on the
LSB, the offending IBOC station is 10 kHz higher (not lower as you'd expect);
and if on USB, then 10 kHz lower.

So you need selectable sidebands to tell, or at least a BFO and notice whether
the noise pitch goes up as you tune up (in which case the IBOC station is higher)
or goes down (in which case the IBOC station is lower), starting from the
interfered-with station.
--
Ron Hardin

On the internet, nobody knows you're a jerk.

 
 
 

Spectrum plot of an IBOC AM station

Post by Kevin Alfred Stro » Thu, 26 Feb 2004 04:40:40



> > That spectrum is consistant with what I heard a few evenings ago around
> > 720 kHz.  WGN's engineer said it wasn't them, and I haven't noticed the
> > noise since then.

> > Has anyone heard the sidebands produced by IBOC?  The best description I
> > can come up with is something like "digital white noise".

> It's just a noise rush, but not white exactly.  The giveaway is that it's on
> only one sideband of the station you're trying to hear.  If you hear it on the
> LSB, the offending IBOC station is 10 kHz higher (not lower as you'd expect);
> and if on USB, then 10 kHz lower.

> So you need selectable sidebands to tell, or at least a BFO and notice whether
> the noise pitch goes up as you tune up (in which case the IBOC station is higher)
> or goes down (in which case the IBOC station is lower), starting from the
> interfered-with station.

[...]

All of this destruction of the radio listening hobby -- and
destruction of _anyone's_ ability to listen to many of the more
distant or weaker stations he can now receive -- is because the
money-men of the media monopolies saw a new digital band as a threat
to their ***. So they squelched it -- they hope -- with IBOC.

As I've said before, IBOC (In-Band On-Channel) digital -- AM or FM
-- is essentially a turkey, technically. It's inferior in almost
every way to a dedicated digital system in a dedicated digital band.

The main reason IBOC is promoted is because a new dedicated digital
band would level the playing field: the present 250-Watt AM
daytimer, once ensconced in the new band, would have just as clear
and clean a signal as the 50-Kw clear channel or the high-power FM
-- just as good fidelity, the same coverage, and 24-hour operation.
Just like your Web site is as clear and as easily accessible as
NBC's.

A dedicated digital band might also be scalable and allow many more
channels for the listener -- hundreds, thousands perhaps. Probably
enough to allow public access (in which anyone can be a broadcaster
for free or nearly free) on an even greater scale than does cable
television or Internet radio.

And that would mean more competition for the big-money men.

And it would mean that competition would now be purely on the basis
of programming, not the sheer signal superiority which the money-men
have paid for.

They want to preserve the _inferiority_ of their smaller
competitors. IBOC does that. They want to maintain the high economic
hurdle to becoming a broadcaster. IBOC does that.

With all good wishes,

--

Kevin Alfred Strom.

News: http://www.redwaveradio.com/
The Works of R. P. Oliver: http://www.redwaveradio.com/
Personal site: http://www.redwaveradio.com/

 
 
 

Spectrum plot of an IBOC AM station

Post by Frank Dresse » Thu, 26 Feb 2004 07:37:56


Quote:

> It's just a noise rush, but not white exactly.  The giveaway is that
it's on
> only one sideband of the station you're trying to hear.  If you hear
it on the
> LSB, the offending IBOC station is 10 kHz higher (not lower as you'd
expect);
> and if on USB, then 10 kHz lower.

I'm not sure I understand.  The spectrum plot shows two symmetrical
peaks off the carrier frequency.  The noise I observed was consistant
with that.

> So you need selectable sidebands to tell, or at least a BFO and notice
whether
> the noise pitch goes up as you tune up (in which case the IBOC station
is higher)
> or goes down (in which case the IBOC station is lower), starting from
the
> interfered-with station.
> --
> Ron Hardin


I turned the BFO on, and scanned across the noise. I didn't think to try
to discriminate between a upper or lower sideband transmission. I was
trying to tell if there were multiple carriers in the sideband noise.  I
don't think there was, but I wasn't checking it out very long.  I played
with it for a couple of minutes, then I got on the computer to check if
there was an announcement of WGN was going IBOC.  There wasn't, and by
the time I got back to the radio, everything was quiet.  It's been quiet
since.

Frank Dresser

 
 
 

Spectrum plot of an IBOC AM station

Post by Frank Dresse » Thu, 26 Feb 2004 07:38:00



Quote:

> All of this destruction of the radio listening hobby -- and
> destruction of _anyone's_ ability to listen to many of the more
> distant or weaker stations he can now receive -- is because the
> money-men of the media monopolies saw a new digital band as a threat
> to their ***. So they squelched it -- they hope -- with IBOC.

As far as I know,  the FCC has stopped all IBOC testing at night in
order to reduce interference with other stations.

Quote:

> As I've said before, IBOC (In-Band On-Channel) digital -- AM or FM
> -- is essentially a turkey, technically. It's inferior in almost
> every way to a dedicated digital system in a dedicated digital band.

> The main reason IBOC is promoted is because a new dedicated digital
> band would level the playing field: the present 250-Watt AM
> daytimer, once ensconced in the new band, would have just as clear
> and clean a signal as the 50-Kw clear channel or the high-power FM
> -- just as good fidelity, the same coverage, and 24-hour operation.
> Just like your Web site is as clear and as easily accessible as
> NBC's.

Didn't the Canadians establish a new digital band?  Is it being heard
much?

Quote:

> A dedicated digital band might also be scalable and allow many more
> channels for the listener -- hundreds, thousands perhaps. Probably
> enough to allow public access (in which anyone can be a broadcaster
> for free or nearly free) on an even greater scale than does cable
> television or Internet radio.

> And that would mean more competition for the big-money men.

> And it would mean that competition would now be purely on the basis
> of programming, not the sheer signal superiority which the money-men
> have paid for.

> They want to preserve the _inferiority_ of their smaller
> competitors. IBOC does that. They want to maintain the high economic
> hurdle to becoming a broadcaster. IBOC does that.

> With all good wishes,

> --

> Kevin Alfred Strom.

Well, maybe, but I don't see the entire broadcast industry rushing to
IBOC.  The night time ban puts a big crimp on IBOC.  IBOC reduces the
bandwidth and fidelity of the main channel.  Also, putting all that
power into sideband noise reduces the power and signal to noise ratio of
the main channel.  People who are annoyed by bad sounding AM radio and
have yet to buy an IBOC radio are more likely to tune out.

People who don't much care about fidelity, and I think that's the
majority of casual listeners, won't much care for IBOC, either.

Frank Dresser

 
 
 

Spectrum plot of an IBOC AM station

Post by Ron Hardi » Thu, 26 Feb 2004 07:49:42


> > It's just a noise rush, but not white exactly.  The giveaway is that
> it's on
> > only one sideband of the station you're trying to hear.  If you hear
> it on the
> > LSB, the offending IBOC station is 10 kHz higher (not lower as you'd
> expect);
> > and if on USB, then 10 kHz lower.

> I'm not sure I understand.  The spectrum plot shows two symmetrical
> peaks off the carrier frequency.  The noise I observed was consistant
> with that.

It's not symmetric around the adjacent channel station being interfered with.

If IBOC is on 700 and you're listening to 710, the the IBOC noise is at 713,
which is the upper sideband of 710.  If you listen to 710 LSB, the noise
disappears.
--
Ron Hardin

On the internet, nobody knows you're a jerk.

 
 
 

Spectrum plot of an IBOC AM station

Post by Frank Dresse » Thu, 26 Feb 2004 08:03:25


Quote:

> It's not symmetric around the adjacent channel station being

interfered with.

OK.  The noise was symmetrical around 720, and I was trying to catch
710.

> If IBOC is on 700 and you're listening to 710, the the IBOC noise is
at 713,
> which is the upper sideband of 710.  If you listen to 710 LSB, the
noise
> disappears.
> --
> Ron Hardin


I live a few miles from WGN's transmitter, and the normal sideband
splatter makes WOR almost unlistenable.  I was just curious about
propagation that night.  A station ID was all I wanted.  If I ever hear
the noise again, I'll listen to it more carefully.

Frank Dresser

 
 
 

Spectrum plot of an IBOC AM station

Post by Stephen M.H. Lawrenc » Thu, 26 Feb 2004 10:59:45

Holy crap, look at those spurs +/- 15kc!

Oh, yeah, IBAC (In Band Adjacent Channel) is
going to save AM!

73,

Steve Lawrence
Burnsville, MN


| Thanks to Bob Gonsett
|
| http://earthsignals.com/add_CGC/KMXE.PDF

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
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Spectrum plot of an IBOC AM station

Post by Davi » Fri, 27 Feb 2004 00:01:17

Canada uses Eureka 147 DAB.  It is slowly gaining an audience.

On Tue, 24 Feb 2004 22:38:00 GMT, "Frank Dresser"




>> All of this destruction of the radio listening hobby -- and
>> destruction of _anyone's_ ability to listen to many of the more
>> distant or weaker stations he can now receive -- is because the
>> money-men of the media monopolies saw a new digital band as a threat
>> to their ***. So they squelched it -- they hope -- with IBOC.

>As far as I know,  the FCC has stopped all IBOC testing at night in
>order to reduce interference with other stations.

>> As I've said before, IBOC (In-Band On-Channel) digital -- AM or FM
>> -- is essentially a turkey, technically. It's inferior in almost
>> every way to a dedicated digital system in a dedicated digital band.

>> The main reason IBOC is promoted is because a new dedicated digital
>> band would level the playing field: the present 250-Watt AM
>> daytimer, once ensconced in the new band, would have just as clear
>> and clean a signal as the 50-Kw clear channel or the high-power FM
>> -- just as good fidelity, the same coverage, and 24-hour operation.
>> Just like your Web site is as clear and as easily accessible as
>> NBC's.

>Didn't the Canadians establish a new digital band?  Is it being heard
>much?

>> A dedicated digital band might also be scalable and allow many more
>> channels for the listener -- hundreds, thousands perhaps. Probably
>> enough to allow public access (in which anyone can be a broadcaster
>> for free or nearly free) on an even greater scale than does cable
>> television or Internet radio.

>> And that would mean more competition for the big-money men.

>> And it would mean that competition would now be purely on the basis
>> of programming, not the sheer signal superiority which the money-men
>> have paid for.

>> They want to preserve the _inferiority_ of their smaller
>> competitors. IBOC does that. They want to maintain the high economic
>> hurdle to becoming a broadcaster. IBOC does that.

>> With all good wishes,

>> --

>> Kevin Alfred Strom.

>Well, maybe, but I don't see the entire broadcast industry rushing to
>IBOC.  The night time ban puts a big crimp on IBOC.  IBOC reduces the
>bandwidth and fidelity of the main channel.  Also, putting all that
>power into sideband noise reduces the power and signal to noise ratio of
>the main channel.  People who are annoyed by bad sounding AM radio and
>have yet to buy an IBOC radio are more likely to tune out.

>People who don't much care about fidelity, and I think that's the
>majority of casual listeners, won't much care for IBOC, either.

>Frank Dresser

 
 
 

Spectrum plot of an IBOC AM station

Post by Frank Dresse » Fri, 27 Feb 2004 04:09:25


Quote:> Canada uses Eureka 147 DAB.  It is slowly gaining an audience.

I thought so.  A seperate band makes sense.  If some entrepeneur thinks
the public really wants the presumed advantages of digital broadcasting,
let him be a pioneer on a new band.

Frank Dresser

 
 
 

Spectrum plot of an IBOC AM station

Post by Kevin Alfred Stro » Fri, 27 Feb 2004 04:23:04

[...]

Quote:

> Well, maybe, but I don't see the entire broadcast industry rushing to
> IBOC.  The night time ban puts a big crimp on IBOC.  IBOC reduces the
> bandwidth and fidelity of the main channel.  Also, putting all that
> power into sideband noise reduces the power and signal to noise ratio of
> the main channel.  People who are annoyed by bad sounding AM radio and
> have yet to buy an IBOC radio are more likely to tune out.

> People who don't much care about fidelity, and I think that's the
> majority of casual listeners, won't much care for IBOC, either.

> Frank Dresser

All very true. But the owners of the media monopolies don't care a
great deal about the success of IBOC or even its widespread
implementation. Their main concern is to _prevent_ the creation of a
new digital band wherein all existing broadcasters would have an
even playing field. IBOC does that -- at least so far.

With every good wish,

Kevin.
--

Kevin Alfred Strom.

News: http://www.nationalvanguard.org/
The Works of R. P. Oliver: http://www.revilo-oliver.com
Personal site: http://www.kevin-strom.com

 
 
 

Spectrum plot of an IBOC AM station

Post by Frank Dresse » Fri, 27 Feb 2004 04:49:19



Quote:

> All very true. But the owners of the media monopolies don't care a
> great deal about the success of IBOC or even its widespread
> implementation. Their main concern is to _prevent_ the creation of a
> new digital band wherein all existing broadcasters would have an
> even playing field. IBOC does that -- at least so far.

> With every good wish,

> Kevin.

We don't have a seperate band for digital radio, but the time brokered
domestic shortwave stations are allowing much of the programming the
networks don't.  Although there isn't any local content.  Anyway, the
radio establishment doesn't seem much bothered by independant
broadcasting.

I think the bigger reason there wasn't a seperate digital band
established is the government plans to auction off spectrum, and setting
aside a band in a prime VHF/UHF region puts a crimp in their budget
estimates.

Frank Dresser