Slashdot Mirror
Broadcast Radio Turns 100
GraWil writes "On Christmas eve 1906, a Canadian physicist named Reginald Fessenden presented the world's first wireless radio broadcast from his transmitter at Brant Rock, MA. The transmission included Christmas music and was heard by radio operators on board US Navy and United Fruit Company ships equipped with Fessenden's wireless receivers at various distances over the South and North Atlantic, and in the West Indies. Fessenden was a key rival of Marconi in the early 1900s who, using morse-code, succeeded in passing signals across the Atlantic in 1901. Fessenden's work was the first real departure from Marconi's damped-wave-coherer system for telegraphy and represent the first pioneering steps toward radio communications and radio broadcasting. He later became embroiled in a long-running legal dispute over the control of his radio-related patents, which were eventually acquired by RCA."
KDKA started broadcasting on November 2, 1920 as the first commercial radio station in the United States. It also claims to be the first radio station broadcasting on a regular schedule. That claim is complicated by the fact that radio prior to 1920 was mostly experimental and good records are not kept for all "experimental" signals of contesting stations. Further, another radio station in North America, XWA-AM in Montréal, Québec, Canada (renamed CFCF-AM on November 4, 1920), began its commercial, regular broadcast programming schedule on May 20, 1920 -- nearly six months before KDKA aired its first regularly scheduled broadcast.
http://en.wikipedia.org/wiki/KDKA_(AM)
I remember listening to school closings and football/baseball games on there growing up. On a good night, 600 miles away, I can still listen to them.
What I find interesting about the history of "radio" is that the word itself wasn't coined until some ten or twenty years after the invention. People used to call it "the wireless" before that. The guy who made up the word "radio" was an advertising expert named Waldo Warren. The same guy was later given the task to create a brand name for some of the early inventions of R. Buckminster Fuller. He came up with the word "Dymaxion", simply by jotting together syllables of random words Fuller used all the time: Dynamic Maximum Tension.
I like it that the word "radio" comes from the same heritage.
The ARRL is sponsoring an on-the-air celebration of the centennial of broadcasting. The Hello Radio campaign has been celebrating the upcoming event throughout most of 2006.
How many broadcasters will let this event go unremarked? That is sad indeed.
"Insanity is doing the same thing over again expecting a different result."
Even microwaves are radio waves as it is a part of the electromagnetic spectrum--it is just much higher in frequency than the traditional broadcast bands. The same can be said of light which is also at a much higher frequency (shorter wavelength) of the electromagnetic spectrum.
The advantage of the microwave region is that a signal can occupy a larger range of frequencies and the wavelength from the low to the high end of the bandwidth doesn't change much due to the inverse relationship of frequency and wavelength. Calling it "satellite radio" is not deceptive except that it is a completely digital stream and the receiver's tuner doesn't necessarily tune to a different frequency for each "channel".
"Insanity is doing the same thing over again expecting a different result."
"clear channel" stations are not allowed to increase power at night. While I haven't specifically mined the FCC database, I can say with considerable confidence that there are fewer than ten AM stations in North America that run more power at night than during the day.
However, "clear channel" stations are not required to *reduce* power at night. Most other stations are, and/or are required to switch to a directional antenna that concentrates all their power in a specific direction.
Technically, "clear channel" refers to the frequency, not to any specific station. For example, 720KHz is a "clear channel", and in theory any station operating on that frequency could call itself a "clear channel" station. Many do.
"clear channel" stations are divided into three classes, A, B, and D. Only one Class A station can exist on a frequency, and that's the dominant station most people think of when they think of a "clear channel" station. This station is allowed to operate 50,000 watts non-directional day & night, and is not required to protect any other station from interference. All other stations on the frequency must protect the Class A station.
For example, on 720KHz, WGN in Chicago is the Class A station. KDWN in Las Vegas is one of several Class B stations on 720; KDWN runs 50,000 watts 24/7, but is required to switch to a directional antenna at night, limiting the amount of power radiated in the direction of Chicago to maybe two or three dozen watts. (I think you can reasonably assume the KDWN transmitter is northeast of Las Vegas!).
Class D stations are those that are not allowed to operate at all at night, or are limited to nighttime powers less than that required for a new station. (generally, less than 250 watts; sometimes as little as one watt. No new Class D stations are being authorized.) An example of a Class D station on 720 is WGCR in western North Carolina, which goes off the air completely at sundown to protect WGN from interference.