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Old December 29th 03, 04:20 PM
David Eduardo
 
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"WBRW" wrote in message
...
The number of such radios pales when comparred to the number represented

by
more typical devices.


Allowing IBOC to take advantage of the weaknesses of "typical" AM
receivers in order to cover up its faults is akin to contructing a
waterfront building according to the parameters of a "typical"
hurricane. Or, it's like manufacturing a car whose lifespan is only
80,000 miles because the "typical" driver only keeps it that long.


The typical AM receiver can not tell the difference between the reduced
IBOC-mandated analog bandwidth and a full NRSC bandwidth. In fact, I fidn
that the reduced transmitted bandwidth sounds better on many radios than
wider bandwidth.

There are 700 million radios out there; most all of them have crummy AM
response.

IBOC offers a future improvement to AM and FM.

For years, the complaints about AM radio have been interference and
poor audio quality. Now, IBOC comes along and in order to "solve"
these problems, it _purposely_ transmits additional interference and
_purposely_ degrades the audio quality even further. Where is the
sense in that!?


It does not degrade analog FM at all; on AM I feel the degradation looks bad
on paper, but in reality it is insignificant and may be an improvment.

The receivers will be below $100 within 12 months, if not sooner. the

prices
will track CD players and DVD players in price declines.


But the prices for IBOC receivers -- if they ever arrive -- will not
be competitive with that of analog radios... just like digital TVs
still cost a lot more than comparable analog sets, half a decade after
their introduction.


The said the same thing about CD players, VHS players and DVD players. I
paid over $700 for my first VHS; $1200 for my first CD player. And the tapes
and CDs were very expensive to start.

The fact that most radio listening is to local stations answers that
question.


Another hypocritical answer. For years, engineers like yourself have
complained about the loss of coverage area that FM Stereo and AM
Stereo allegedly cause.


I don't. FM stero may cause more multipath in some areas, but very very few
FMs are mono. AM stereo sucks. There are reasons beyond coverage (which is
not generally affected per se) that doomed that system... most in the hands
of the FCC.

Many stations on both bands have discontinued
stereo broadcasts, just to squeak a few more miles out of their fringe
coverage.


In the case of FM, this is mostly with low powered stations and very few of
them.

In AM, it is because the system never took off, as AM was already dead for
music and fidelity when the FCC finally mandated one system.

But now, suddenly that doesn't matter anymore? Now, with
IBOC, listeners outside the primary coverage area are suddenly of no
importance?


Listeners outside the metro are do not afford most stations any opportunity
for extra revenue. I am with two Los Angeles stations that are generally in
the top 10 in Riverside, a separate market. That coverage and audience is of
no value at all; it gets no revenue,k it is too far away to become involved
with and not useful.

But you just wait... once mutual IBOC interference from an adjacent
station comes back to bite these stations in the butt, suddenly _then_
they will start complaining about it. It's like a guy who lets his
dog **** all over his neighbor's property and doesn't care about it --
but once somebody else's dog comes and ****s on his _own_ front lawn,
then he suddenly is concerned about it.


About 90% of FM listening is in the 70 dbu contour; in metros, the 10 mv/m
contour on AMs holds most of the listeners. Most Ams today don't put a 10
over the entire market, and are generally crippled from the start.

And I have heard AM IBOC and it sounds better than many highly

compressed
FMs I A/B'd with. The new algorithm is excellent.


Yeah, if you like digital aliasing artifacts screeching in your ears.
The "spectrally replicated" treble response of AM IBOC is akin to
fingernails scratching a chalkboard.


I am listening daily to an LA music AM in IBOC digital and the audio is
crisp, nice, clear, and very listenable. It is nothing like you say.

A few weeks ago, I listened to
XM for about 2 hours in a coworker's car, and the screechy fake treble
actually gave me a headache -- and that's with a bitrate nearly twice
as high as AM IBOC. The only way I could live with either IBOC or XM
is if I turned the treble control all the way down.


XM and IBOC have different systems.

On 99% of AM receivers, there is no analog degradation because the

receivers
are not wide enough to detect the difference.


Not quite... the NRSC tested four receivers which are supposed to be
the most representative of "typical" AM radios. Only one of the
radios (a Delphi car radio) was narrowband enough to not exhibit any
degradation. But the three others did have degraded audio with IBOC
in use, the worst being a Sony boombox. iBiquity's excuse for this
was that according to their testing, the degradation wasn't bad enough
that it would cause most listeners to change the station.


We tested with a bunch or receivers, rnging from clock radios to boom boxes
to walma n type devices. None of us could tell any significant difference in
A/B testing. By the way, the NRSC test you refer to was before the revised
IBOC algorithm and not necessarily on a station with a wide bandwidth
antenna system.

But the
point is, according to the NRSC tests, 3/4ths of today's most popular
radios _will_ have degraded audio when AM IBOC is in use.


Near 3 weeks of operation, not one listener comment on the analog signal.

You are letting the cart get ahead of the horse. The CES is going to be
filled with IBOC equipment, and I believe some at much more affordable
prices.


Yeah, like B.E.'s IBOC exciter, with a list price of over $22,000...
that's a steal!


That is actually pretty reasonable as broadcast gear goes. An Optimod or an
Omnia are in the 10 k range... good equipment is costly... our last morning
show boards cost around $80 thousand each.

Many stations, especially those doing block, brokered programming, will

not
gain initially from IBOC. those with decent signals can gain a lot.


Ah, equality at its best... the big 50 kW stations can enjoy "digital"
reception for their local listeners, no matter how much they hash all
over the band, while the smaller stations get the short shrift, and
may not even be able to use IBOC at all.


No, they may not. They are brokered or ethnic because they can not compete
on signal alone. So they specialize. No one asked them to file for
insufficient facilities, or not to upgrade in time as markets grew.

Case in point... 1530 WSAI. When they're transmitting IBOC at night
(as they have been constantly), the "hash" to adjacent channels is so
bad, it can even be heard on the _studio monitor_ of a neighboring
station, 1520 WKWH in Shelbyville, IN.


Does WKWH have its studio inside its interference free night contour? Many
AMs have studios in locations where the night signal is unlistenable. And
WSAI is direcitonal at night, protecting Sacramento. Of course, WKWH only
has 250 watts at night.

IBOC can only be run 6 AM to 6 PM or sunrise to sunset, whihever is greater.

Any experiments were to determne the insertion level for IBOC for porposed
night operation.