[BC] The solution to the IBOC dilemma: "XFM"!

[Phil Alexander]

On 14 Jul 2005 at 17:26, Kevin Tekel wrote:

> Even the most die-hard IBOC supporters here can admit that the "hybrid"
> AM version of IBOC has some serious flaws, and may not be workable in the
> long run.  So what's the solution to that dilemma, aside from the choice
> of doing nothing and leaving today's analog AM (in Stereo, where
> available) as-is?

Moving on to full digital as soon as possible.

> here in North America, we use 76-82 MHz
> for VHF TV Channel 5 and 82-88 MHz for Channel 6.  But since the big
> Japanese electronics manufacturers have already been making home-market
> radios which tune 76-108 MHz on FM, why not make use of this extra
> spectrum for traditional analog FM broadcasting (with or without IBOC or
> FMxtra)
> once the DTV transition is complete, at which point the VHF-Low TV band
> (Channels 2-6) can be easily vacated?

Because Congress told the FCC to auction it for other purposes to bring 
in the most billions.

> *That's* the answer to the AM radio dilemma, courtesy of a 10-year-old's
> curiosity.  

Right. Lose the over the horizon capability of MW for VHF and leave the
country crippled in time of disaster. Some solution. Right now, if all
of Florida goes out in a hurricane, WSB is on the air. Really!

> Get the radio manufacturers to start equipping U.S.-model
> receivers with 76-108 MHz FM coverage, and migrate the most suffering AM
> stations to the new 76-88 MHz FM spectrum.  At first, I'd migrate all or
> most of the Class C "graveyard channel" and Class D (ex-)daytimers to FM,
> and leave the Class A and B stations on AM, where they will have room to
> move to the vacated frequencies, increase their power, and relax or
> eliminate their directional patterns, to provide the best possible
> traditional AM radio coverage and quality.

Uh, Kevin, I hate to tell you this, but a new FCC Chairman has already 
been appointed.
 
> Also, as part of the introduction of this theoretical eXpanded 76-108 MHz
> FM band in North America, 

Which can't happen because the spectrum is already allocated.

> I would also propose changing our FM pre-emphasis curve from 75 to 50 
> microseconds -- both to ensure complete compatibility with "world-band" 
> FM radios designed for the Japanese market, and to help restore a bit 
> of extra "sparkle" to today's heavily-squashed analog FM processing wars.

Any station that wants to can run from FLAT to 75 us NOW. Pre-emphasis has
been optional for several year.

> p.s. There's also the gap between Channel 4 and Channel 5, covering 72 to
> 76 MHz, which could also be potentially used for "XFM" radio broadcasting.

Right, those frequencies are assigned and I'm not sure you or the FCC
would have much success taking them. <g> Little thing like NG use,
radio astronomy and aircraft marker beacons. GET REAL! The 75 MHz 
marker beacons are standard world-wide and you DO NOT touch NG 
allocations or the FCC will be the least of your worries. <gggggg>
Radio astronomy is not easily moved either. Kevin, there is much more
to the business of radio engineering that satisfying your listening
pleasure.


Phil Alexander, CSRE, AMD
Broadcast Engineering Services and Technology 
(a Div. of Advanced Parts Corporation) 
Ph. (317) 335-2065   FAX (317) 335-9037





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