In 1953, the FCC approved the CBS Mechanical Color system, a system of color television that, if implemented, would have simply left millions of black and white receivers obsolete (without a converter). In that nickel plated, vacuum tube era, the CBS Color system was not practical due to the bulky mechanical disk and shortages of material (we were fighting the Korean War at the time, a “police action”) the CBS system was quickly withdrawn by the FCC and CBS. The current color system (until 2/17/09), NTSC, was an electronic color system, which is compatible with existing black and white television sets. The CBS color system was not practical, due to the current state-of-the-art of television in 1953. NTSC eventually got the blessing of the FCC as THE color system for the USA.
Fast forward to 2007. There’s a saying that “you can’t make a silk purse from sow’s ear”. While HD FM is practical (to a point, but with somewhat limited coverage), all indications point to the opposite for HD AM. Everybody knows that nighttime skywave reception is a way of life for AM, whether you’d purposely want to listen to out-of-town stations, or if you have wanted to listen to a semi-local station and find it to be two to three stations deep in co-channel interference. Well, that’s the nature of the beast. Adding loud white noise (a by-product of IBOC transmission) to an already congested and mismanaged portion of spectrum is not the way to regain listeners. We’ve seen the results of nighttime IBOC reception with a company, who owns two major adjacent channel 50,000 watt blowtorches, discontinuing the nighttime IBOC due to mutual interference concerns and from actual complaints from listeners.
The IBOC system requires a station to brickwall their analog audio purposely to 4 to 5 kHz bandwidth, to protect the two IBOC sidebands used for digital broadcasting. The result, what used to be comparably wideband audio is now limited to the sound of a dialup phone line. Adding adjacent channel white noise to the mix, and you’re wondering why the band is losing listeners? Which brings up the question.., is IBOC the really the only way to bring AM to the digital age? Why not revisit Kahn’s CAM-D or possibly DRM? IMHO, the current version of AM HD should be revisited before the AM band is rendered completely useless. The interference issues are not going away anywhere soon without a definitive decision on how to deal with it. And there is nothing wrong with AM stereo (C-QUAM). Had the FCC mandated the C-QUAM sooner (rather than letting the marketplace decide) and mandated its’ use in portable stereo radios (like Walkmans and boom-boxes), we might have seen better results today with AM Stereo.
Like the CBS color issue, where the FCC revisited it and eventually decided to go with NTSC color instead, maybe the Commission should revisit HD AM and consider other alternatives or have Ibiquity try to rework their system to where adjacent channels are not subject to unwanted interference. I’m wondering if a hybrid IBOC/day and C-QUAM night configuration might be a possible temporary fix for the moment (like what WLS was doing). The chipsets are already out there to automatically handle both systems with ease.
Just a thought.
Fast forward to 2007. There’s a saying that “you can’t make a silk purse from sow’s ear”. While HD FM is practical (to a point, but with somewhat limited coverage), all indications point to the opposite for HD AM. Everybody knows that nighttime skywave reception is a way of life for AM, whether you’d purposely want to listen to out-of-town stations, or if you have wanted to listen to a semi-local station and find it to be two to three stations deep in co-channel interference. Well, that’s the nature of the beast. Adding loud white noise (a by-product of IBOC transmission) to an already congested and mismanaged portion of spectrum is not the way to regain listeners. We’ve seen the results of nighttime IBOC reception with a company, who owns two major adjacent channel 50,000 watt blowtorches, discontinuing the nighttime IBOC due to mutual interference concerns and from actual complaints from listeners.
The IBOC system requires a station to brickwall their analog audio purposely to 4 to 5 kHz bandwidth, to protect the two IBOC sidebands used for digital broadcasting. The result, what used to be comparably wideband audio is now limited to the sound of a dialup phone line. Adding adjacent channel white noise to the mix, and you’re wondering why the band is losing listeners? Which brings up the question.., is IBOC the really the only way to bring AM to the digital age? Why not revisit Kahn’s CAM-D or possibly DRM? IMHO, the current version of AM HD should be revisited before the AM band is rendered completely useless. The interference issues are not going away anywhere soon without a definitive decision on how to deal with it. And there is nothing wrong with AM stereo (C-QUAM). Had the FCC mandated the C-QUAM sooner (rather than letting the marketplace decide) and mandated its’ use in portable stereo radios (like Walkmans and boom-boxes), we might have seen better results today with AM Stereo.
Like the CBS color issue, where the FCC revisited it and eventually decided to go with NTSC color instead, maybe the Commission should revisit HD AM and consider other alternatives or have Ibiquity try to rework their system to where adjacent channels are not subject to unwanted interference. I’m wondering if a hybrid IBOC/day and C-QUAM night configuration might be a possible temporary fix for the moment (like what WLS was doing). The chipsets are already out there to automatically handle both systems with ease.
Just a thought.