Re: [IRCA] IBOC/analog reception comparisons.

["Craig Healy" <bubba@xxxxxxxxxxxxxxxxxxxx>]

> 1.      Kahn is hardly "not of radio."  He invented the first analog AM
> 2.      Kahn's rejection of the FCC AM stereo decision and his lengthy
legal
> 3.      Kahn was contentious long before IBOC / HD were even dreamed of.
The

No real argument there.  Had Kahn been better at people skills and
promotion,  and better funded, it would have been very different.

> 4.      AM HD sounds very, very good. In fact, it sounds "near FM"
quality,

There is no question it does sound better than existing AM radios.  However,
open up the bandwidth to where it could be, and use technology such as the
new Motorola analog chip, and the difference is much less.  I would love to
hear it compared to the WLW hifi transmitter of years past and a really good
analog radio such as built in the late 30's.  I would bet the difference
would be much less.  Even the old Western Electric rig and a good Zenith
floor console would likely give it a run for the money.

> 5.      FM HD sounds better than analog FM, in part because it does not
have
> the pre-emphasis curve which was an answer that worked in old technology
> that, unfortunately, is not one we could eliminate because of, precisely,
> those billion radios.

It would have been much better to eliminate the preemphasis and move the
pilot up to 76kHz.  That, at least, would have left the old radios able to
receive in mono with a tweak of the treble control which most have.  Partial
compatibility is better than none.

Again, the JVC will decode to about half the useable radius of a good analog
signal.  I think where we differ is our definition of "good analog signal".
My benchmark is where the audio is pretty much noise free.

One of my clients is nearly top rated in Providence from a transmitter site
30 miles east.  HD Radio would simply not decode there.  Were they to go HD,
the signal would miss most of their target market.  And that's without any
other stations' signal intruding on top of their digital sidebands which
would reduce it further.

My experience is that external noise, be it ignition or power line, blocks
the decode.  One great thing I can see out of all this is if the NAB makes a
concerted effort to lean on auto manufacturers and utilities to actually
comply with Part 15.

The proprietary nature of the codec and data stream trouble me, and
apparently Bill Gates.  If this were released to public domain, it would
accelerate things a lot.

And we have yet to see if any lawsuits will be filed against the
interference.  All it takes is one in federal court to bring the whole
rollout to a screeching halt.

I still see big problems, and from reading Radio World, others are starting
to grumble.

Craig Healy
Providence, RI


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