Flying VFR in New York City’s Hudson River Corridor, you’re now required to report abeam “Alpine Tower,” a longtime FAA visual reporting point. I was recently reminded of the radio pioneer behind that tower. Don’t know Edwin H. Armstrong? Know why there is no Channel 1 on your TV set? Know why you can listen to radio without headphones?
Alpine Tower is distinctive with its three 150-foot crossbeams on a squat 400-foot tower topping out at 925 MSL. As a “Jersey Boy,” I prided myself knowing the name derives from its location in Alpine, New Jersey, on the Hudson’s west bank north of the George Washington Bridge.
Turns out, Alpine Tower was the start of commercial FM broadcasting, a technology Armstrong (a mostly forgotten radio pioneer) invented. The tower also symbolizes the tragedy of Armstrong’s life filled with patent suits and a frequency spectrum battle nastier than LightSquared vs. GPS.
You know the story if you read Tom Lewis’ 1991 Empire of the Air (or saw the 1992 Ken Burns PBS documentary.) RCA’s David Sarnoff asked radio genius Edwin Armstrong to eliminate static from AM (amplitude modulation) radio, which dominated American broadcasting before TV. Instead of developing “a little black box” to fix AM, Armstrong invented frequency modulation (FM) — an entirely new transmission method. Sarnoff feared it would obsolete his AM empire. Besides, RCA was developing commercial television. Who wanted better radio?
Armstrong was quickly kicked out of RCA’s experimental lab in the Empire State Building. He soldiered on at Columbia University and at the FM transmitter he self-financed and built at Alpine in 1938. In 1940, the FCC authorized FM broadcasting in the 42-54 mHz band that was to have been TV Channel 1. (Now you know.)
Modulating frequency, rather than amplitude (signal strength), FM was superior to AM. It could reproduce almost the entire frequency range of human hearing. For the first time, broadcast music was realistic to the ear. There was no static from bursts of electrical energy, as from lightning. And FM stations could transmit farther or use lower power and they didn’t interfere with each other. Only the strongest FM signal was heard, not multiple stations simultaneously.
FM signals penetrated the ionosphere rather than bouncing back to earth creating nighttime interference a thousand miles away. “Skip distance” no longer required power reductions or station shut-downs after sundown. (FM’s ionosphere penetration later enabled radio communications with spacecraft.)
Armstrong’s W2XMN (later WFMN) began transmitting from Alpine Tower in 1941 on 42.8 mHz. It could be heard loud and clear 100 miles away at the tip of Long Island. The innovator next put FM on radio’s Yankee Network throughout New England using inexpensive FM-based relays to local stations. The industry fought back. AT&T, for instance, wanted to protect its role in distribution of network radio by land line.
The big blow, however, was the old bugaboo of frequency (spectrum) allocation. In 1945, RCA got the FCC to move FM broadcasting to today’s 88-108 mHz band — justified, in part, by the supposed threat of the 1948-49 sunspot season. So by FCC fiat, a half-million new FM radios were obsolete. I first learned of this as a kid, discovering a discarded FM radio with “wrong” dial numbers in my aunt’s attic.
Police radio took over FM’s original frequencies (putting an end to listening in on local cops with your living room set.) But the big impact was on FM broadcasting, setting back its growth a decade or more. Most broadcasters could not afford to re-equip stations so soon after their initial investment. FM did not achieve aggregate industry profitability until 1975, and then only after the introduction of FM stereo.
The impact on Armstrong was far worse. After decades fighting patent suits, Armstrong took his life in January 1954. On March 31 that year, WFMN was switched off.
But Alpine Tower is still in use today, and played a key role after 9/11 when transmitters atop the World Trade Center tumbled. A week later, New Yorkers got back five of their TV stations from back-ups on Alpine Tower.
Edwin H. Armstrong invented key basic technologies making modern radio and TV possible. Their technical names, some derived from Greek, can be tough to grasp today. We take it all for granted. But Armstrong’s regenerative circuit (1912) amplified radio reception so it could be heard through loudspeakers, not just headphones. His super-heterodyne circuit (1918) made home receivers both affordable and user-friendly in the 1920s. Heck, even the sound on broadcast television is transmitted via FM, invented by Armstrong in 1933. And for that he wasn’t paid a dime in his lifetime.
Perhaps all that flyers have to remember Armstrong is Alpine Tower. Give him a shout-out as you transit or sightsee along The Corridor. But first, report “Alpine Tower” with your type, altitude and direction of flight on 123.05.Top photo by David Brenner
© 2013 Drew Steketee All Rights Reserved