Re: [IRCA] Another ridiculose perspective on IBOC

["Bob Young" <youngbob53@xxxxxxx>]

Where does this leave the vast majority of us who couldn't care a hoot about 
getting new radios and wouldn't, and in fact may have 5,000-10,000 or more 
invested in this 85 YO technology that works great without IBOC?

Bob Young
Analog, MA
R-390, (2) R-390A,(2) SP-600, Sp-400, (2) Sp-200 (2) R-388, HRO-60, HRO-50, 
HQ-180, SX-28A. and many others.

Does iNiquity have a right to make all those fine radios obsolete? And also 
the other 500,000,000 radios in existence (don't quote me on the figures, 
just a wild guess.) If a technology doesn't work with every radio made 
worldwide since the early 20th century, it is the technology not the radios 
that are at fault, his whole premise is ridiculose.How long is this dead 
horse going to be whipped?


>From: Scott Fybush <scott@xxxxxxxxxx>
>Reply-To: Mailing list for the International Radio Club of 
>America<irca@xxxxxxxxxxxxxxxx>
>To: ABDX@xxxxxxxxxxxxxxx,        Mailing list for the International Radio 
>Club of America<irca@xxxxxxxxxxxxxxxx>,        nRC-AM <am@xxxxxxxxxxx>, 
>dxhub@xxxxxxxxxxxxxxx
>Subject: [IRCA] Another perspective on AM IBOC,from the broadcasters' 
>mailing list
>Date: Tue, 27 Mar 2007 11:25:40 -0400
>
>This caught my attention over on the [BC] mailing list, and I suspect it
>may stir up some discussion on the DX lists:
>
> > I have been investigating some of what has been said on this
> > list about IBOC on AM. It appears as though it is really a
> > receiver problem. Don't get me wrong. I'm not advocating
> > trashing 150 bazillion conventional AM radios so that IBOC
> > will work. Instead, as I am beginning to understand the
> > technology, if an AM radio was designed with more modern
> > technology, digital demodulation of AM with a wall filter,
> > there would be no buzz. There really is plenty of bandwith
> > available for IBOC on AM. The feds were not bamboozled.
> > The problem is that AM radios of conventional design,
> > superheterodyne with envelope detectors, cannot handle the
> > adjacent channel IBOC interference at reasonable cost.
> >
> > What the industry really needs is a decent AM radio using
> > modern technology. Such a radio would directly digitize
> > incoming spectra. AM would be demodulated by multiplication
> > of the digitized data with the selected frequency. The
> > resulting 'garbage' would be subjected to a FFT, the bins
> > outside 10 kHz zeroed out, then the inverse FFT would be
> > taken. The result would be a very clean AM signal with
> > no response beyond the 10 kHz passband (9 kHz for some
> > foreign countries), and no intermodulation from out-of-band
> > responses. The same kind of preselection would be used for
> > IBOC digital. You just don't demodulate the AM signal to
> > baseband before digital processing. When I say
> > "no intermodulation," I am talking 96dB down. Since a
> > typical S/N of off-the air AM signals seldom exceeds
> > 60dB, the intermodulation is 30 dB below the noise so,
> > in fact, it is truly "no." Sixteen bits is 65536:1 =
> > 20 log (65536) = 96.32 dB
> >
> > In the past, such a receiver was incredibly expensive.
> > Nowadays, we have inexpensive components that can handle
> > these low bandwidth signals at very low cost. Remember
> > that "real-time" for AM is 10,000 changes per second --
> > truly trivial. For accurate replication of the RF
> > component, you would need to sample something like 10
> > times over-sampling. This means you need a 20 MHz 16-bit
> > ADC. These things are now cheap, $35.00/1000. You can
> > even get a whole development system for $158.00!
> > Goodle "16-bit DAC 20 MHz" and see for yourself. Once
> > somebody starts producing a million radios per month
> > the price would likely drop to the $5.00 range.
> >
> > So, I think that instead of complaining that the new
> > technology is not compatible with 85 year-old radio
> > design, some entrepreneur(s) should take the bull by the
> > horns and develop a decent radio. They don't actually
> > need to get such a radio into production. Leave that
> > for the Pacific rim. What they need to do is generate
> > the "IP" intellectual property with as much as possible
> > embedded into a single chip. Then they license this
> > technology and, perhaps, the chip design. There are
> > lots of "radio" engineers who are now quite versed
> > in software. A development kit and some (sometimes
> > not too) pleasant software debugging time, would
> > establish the viability of the digital radio approach
> > for conventional AM. Then you could attract some
> > investors. All words and ideas presented here are
> > placed into the Public Domain. Get to work!
> >
> > In the meantime, read my book:
> > http://www.AbominableFirebug.com
> >
> > Cheers,
> > Dick Johnson
>
>_______________________________________________
>IRCA mailing list
>IRCA@xxxxxxxxxxxxxxxx
>http://montreal.kotalampi.com/mailman/listinfo/irca
>
>Opinions expressed in messages on this mailing list are those of the 
>original contributors and do not necessarily reflect the opinion of the 
>IRCA, its editors, publishing staff, or officers
>
>For more information: http://www.ircaonline.org
>
>To Post a message: irca@xxxxxxxxxxxxxxxx
>


_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://montreal.kotalampi.com/mailman/listinfo/irca

Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers

For more information: http://www.ircaonline.org

To Post a message: irca@xxxxxxxxxxxxxxxx