You’ve explicitly asked two questions: (1) What finally pushed FM into a position where it could dominate? (2) What will have to happen to allow digital radio to come into its own in the US?
Before I answer those questions, I first have to answer a third question that was implicit in your first: What kept FM, despite its obvious advantages, from becoming dominant for so long?
Wideband frequency modulation was developed privately by Edwin Howard Armstrong, a professor of electrical engineering, in his basement laboratory at Columbia University. His work was not supported with corporate money, much less done in a corporate environment.
Armstrong was known as “the Major,” a reference to his days in the Army Signal Corps during World War I, when he developed the superheterodyne. He became independently wealthy in the early 1920’s by selling RCA exclusive rights to the superhet (he was allowed to own the patent and license it for commercial uses while the government retained the right to use it royalty free).
FM was privately demonstrated for RCA engineers during the summer of 1934, and they were privately very enthusiastic about it. FM signals were transmitted from the top of the Empire State Building, using the antenna (and finals) of RCA’s experimental TV station. The power was only 4,000 watts. The FM receiver was in the Haddonfield home of an RCA engineer. During a thunderstorm that made both KYW and WCAU unlistenable, the experimental FM receiver was able to clearly copy not only NBC Red on the main channel, but also NBC Blue (which became ABC in 1943) and a facsimile of the front page of the New York Times on FM subcarriers.
But RCA CEO David Sarnoff saw little promise in a superior aural service. He was far more interested in developing television. What’s more, the ability of FM stations to form networks without AT&T landlines made it not only a minor threat to AT&T, but also a serious threat to RCA’s NBC networks, and even to rivals CBS and Mutual, raising the spectre of more program choices from new start-up networks operating on a shoestring budget. That’s why the FCC was pressured into kicking FM out of its pre-war band and relocating it in its present three-meter band in 1945—an action that set FM back a decade by making all existing transmitters and receivers obsolete overnight.
An interesting side note, Pab, since I know that you live at the fringe of the Philadelphia market: WFLN, as recently as the early and mid-1950’s, used to carry some of the old WQXR Network offerings by picking them up off the air from an Allentown station that picked them up from WQXR. So the concept of a network without landlines survived here and there at least that long. Of course, that was before the advent of GE-Zenith stereo, with its noisy double-sideband, suppressed-carrier stereo difference signal.
In his landmark 1936 paper, Armstrong himself noted the superiority of FM subcarriers. But in 1961, transistors (never mind chips!) were still found mostly in portable radios, and the extra tubes for the Crosby FM stereo system, which used an FM subcarrier for the difference signal, would have made a significant difference in the cost of receivers. And having a medium-band, if not a wideband, subcarrier would have left no room for the SCA services on which so many FM stations were absolutely dependent financially. That’s why to this day we’re stuck with a noisy, half-AM system for stereo FM. If a Crosby-type all-FM system had been selected,
Returning to the question of why FM didn’t take off earlier, consider the fact that it wasn’t being promoted. The majors were just squatting on the FM assignments, but did nothing to protect their interests in the FM band, much less promote FM. As recently as 1963, CBS didn’t care when the late Dave Kurtz applied for a Philadelphia short-spaced co-channel to their NYC O&O. Today that station is WBEB – B101, the most successful independent in the country.
Contrary to what KeithE4 said above, simulcasts of sister AM’s wasn’t limited to small markets. In many major markets, about half of the FM stations were simulcasting AM programming all or part of the time. And of those that weren’t, not even the “Beautiful Music” stations attracted only “geezers,” if by that you mean listeners over 60, or even over 50. They had a significant 35-44 share. And jazz stations attracted some college, and even high school, listeners (like me).
But Keith got one thing right. It was the rise of “underground” or “progressive” rock stations appealing to the high school and college kids in the late Sixties – together with the gathering momentum of pioneering all-stereo “BM” stations like WDVR (now AC B101) appealing to their parents – that marked the real beginning of FM as a mass medium.
And let’s not forget the rise of album rock, and the interest that generated in component stereo systems (usually with receivers instead of amplifiers), as a factor in FM’s growth.
Still, FM’s aggregate Arbitron share nationally didn’t surpass that of AM until Spring 1978, by which time FM penetration in cars had finally reached critical mass.
Now what will it take for digital radio to succeed in the US?
Don’t expect it to work out at all on AM. The laws of physics preclude that.
But the prospects on the FM band aren’t much better. While not nearly as bad as medium wave, VHF is still not very suitable for digital signals. Consider that the FCC granted WPVI’s request to quadruple its power on channel 6 after the analog shut-off. (Yes, WHYY is still on channel 12, but that’s much higher in the spectrum – and it’s still more vulnerable than the UHF signals. Remember that KYW-TV and WCAU are actually on channels 26 and 34.)
And if FMeXtra works better that Iniquity’s “HD” FM, that’s only because the digital signals of the former are subcarriers of an analog FM signal!
You also have to remember who developed “HD” IBOC. CBS was a key player in the USA Digital Radio consortium. And it was CBS Labs that came up with the pathetic FMX system (which had nothing to do with FMeXtra). See http://en.wikipedia.org/wiki/FMX_(broadcasting)
If digital aural broadcasting ever succeeds, it will be through broadband internet. But wireless internet will not – can not – provide the bandwidth needed for audio that equals analog FM under good conditions. So I think that analog aural broadcasting will remain dominant for the foreseeable future.
Finally, I have no patience with those who try to draw a false parallel between the struggles of FM in its early days, when the dominant forces in broadcasting were trying to suppress it, with the problems of the Iniquity IBOC system today, when the majors, at least initially, were solidly behind it. Their arguments are self-serving and mendacious. Few stations have increased FM IBOC power, because there’s obviously no ROI. It’s just a matter of time until both “HD” and the company behind it disappear. And good riddance!
