Broadcasting 101 (Basics)

Index Back to the Index for more choices.

This is a work in progress. Questions and answer will be added as necessary.

Here are some basic questions people have been asking....

Please note most of the information on this page comes from a special report Broadcasting magazine did on the broadcasting industry's fiftieth year. That special issue (Nov, 2, 1970) gave highlights of each issue since publication began in 1931.

Therefore, all dates after 1931 are the dates of that issue of the magazine. That date will differ from the actual date the event happened.

I will also be using the terms kilocycles (kc) and megacycles (mc) since the terms kiloHertz (kHz) and megaHertz (mHz) did not come into use until the seventies (or so).

(Another account says that Nikola Tesla invented radio ahead of Marconi.)

1899 - Marconi sends wireless signals across the English Channel.

1901 - Marconi, in Newfoundland, receives Morse Code letter "S" transmitted from Poldhu, England.

1906 - Dr. Lee de Forest invents three-element vacuum tube, havins a filament, plate, and grid.

1912 - Titanic sinks. David Sarnoff was not at the Wanamaker Building in New York receiving signals. It makes interesting reading, but it never happened.

1920 - WWJ, Detroit (August) and KDKA Pittsburgh (November) both start regular broadcasting.

1922 - The superheterodyne as a broadcast receiver is demonstrated by inventor Edwin H. Armstrong.

Television was being developed mainly by Philo Farnsworth.

AM Broadcast Band - In the early days radio stations went on the air using two different frequencies. More and more stations went on the air and the Federal Government decided something had to be done to clear up all this chaos. Hence, stations were assigned frequencies and spread out over several kilocycles (the old term) of spectrum.

Many listeners enjoyed searching for distant signals (DX-ing) in those days and some stations would sign off early or, some days, not go on the air at all so listeners could listen to stations far removed from their city of residence.

The broadcast transmitters in those days didn't "muddy" up the broadcast band with their signals so hearing stations many hundreds of miles away was very common. In the last few decades poorly designed transmitters and a more crowded broadcast band have made DX-ing more difficult.

To make matters worse, the Communications Act of 1996 (signed by President Bill Clinton) made it easier for big companies to acquire large quantities of broadcast stations. Big companies like profits and programming is secondary to them, therefore they fill a station's programming day with cheap and easy network, or automated, material. Feed the masses music (heavily researched) and commercials, forget about programming that is interesting and necessary for daily life.

Now, instead of being able to hear unique programming from stations not in your own area (coming into your city at night) you might hear the same programming on your local station from a station that's far away.

In the opinion of this reporter, "Phooey!" to big corporations!

Now, to the definition... The broadcast band is the band of frequencies extending from 535 to (now) 1705 kiloHertz. Each of the 117 frequencies are designated by their center frequency (535-545 kHz is known as 540 kHz).

The broadcast band has slowly evolved into what we know it today. An article in Broadcasting magazine (January 1, 1934) said that the broadcast band had been widened to include 1530, 1550, and 1570 kilocycles with 20 kc spacing for experimental operation (but with authority to broadcast commercial programs). The goal was high-fidelity broadcast transmissions.

In September of 1940 the FCC ordered shifts in operating assignments for standard broadcasting stations in accordance with the North American Regional Broadcasting Agreement of December 1937. The change was to take effect March 29, 1941. It was reported that there were no problems on the day that the switch was made.

Because the signals on the AM broadcast band travel farther at night than in the daytime the Federal Government designed several classes of stations.

A "Dominant Station" meant that the station pretty much had the channel all to themselves.

A "Secondary Station" meant that the station was on a clear channel, but there were other stations also using that frequency.

"Regional" and "Local" stations had a shorter range than the first two classes and therefore had to share their assigned spots with hundreds of other stations.

It was easier to DX the dominant stations because at night they didn't have any interference on their frequency, and few had co-channel (nearby) interference.

DX-ing regional and local stations meant staying up late at night and listening for transmitter tests. This meant daytime only stations (those with no operating hours after sunset) and stations with higher daytime (than nighttime) powers would be on the air testing their transmitters and making sure they were on their operating frequency. (Their signal was being measured by an independent measuring service.)

The AM band's extention to 1700 kHz came a few years ago when the FCC decided to allow stations operating in the daylight hours only, or in a very crowded area of the dial, to move to the newly expanded band. The only problem being the slow appearance of radios capable of receiving those frequencies.

Was there ever a Channel One on TV? Yes, there was, a long time ago.

Before World War II thirteen channels were allocated in the VHF band by the FCC.

According to Broadcasting magazine (Nov. 1, 1937) the FCC allocated 75 channels with 40 kc separation (41.020 mc to 43.980 mc) for "apex" stations and 19.6 mc bands for television (44-108 mc) with 16 channels in the 30-40 mc band for relay stations.

In an April 1st (1940) issue of Broadcasting magazine it was reported that the FCC had suspended the order for limited commercial broadcasting of TV, had censured RCA for sales efforts which were seen as an attempt to freeze TV standards at the level in use at that time. Just a few weeks earlier it had been reported that RCA Had cut the price of TV receivers and wanted to have 25,000 sets in the New York City area where RCA had established an experiemental station.

June 1, 1940 (Broadcasting magazine) commercial operation authorized for FM, operation in the 43 to 50 mc band.

May 1, 1944, CBS proposes starting off postwar TV with high-definition , full-color pictures, broadcast on 16 mc bands. Of course, the CBS color system consisted of a large, spinning wheel in front of the TV screen. The broadcasts were not compatible with black and white receivers.

January 16, 1945. TV band is divided.

June 4, 1945. In a joint request FM Broadcasters Inc and Television Broadcasters Association ask FCC to allocate 44-108 mc immediately; FM to get 50-54 mc for educational use, and 54-68 mc for commercial operation. TV to receive 68-74 and 78-108 mc. But, one month later, the FCC decided to allocate 88-106 mc to FM. TV gets: channel 1, 44-50 mc; ch. 2-4, 54-72mc; ch. 5-6 76-88 mc.

May 10, 1948, FCC orders into effect earlier proposal assiging TV channel 1 (44-50 mc) to nongovernmental fixed and mobile services, denying FM spokesmen's pleas for that channel for use in FM network relaying; also gives FM stations in 44-50 mc band until the end of the year to move to the 88-108 mc band; issues proposed new expanded TV allocation table; calls for hearing on feasibility of TV use of frequencies above 475 mc.

July 18, 1949 Plan to add 42 UHF channels to the present 12 VHF channels, with another 23 - 28 UHF channels reserved for experimental television.

April 3, 1950 RCA shows its new tri-color picture tube; calls for adoption of compatible color standards.

September 4, 1950 Color Television Inc announces new compatible "dash sequential" system of color TV; petitions FCC t reopen color hearings.

October 16, 1950 FCC approves CBS color, effective November 20; CBS promises 20 hours per week of color programs within two months. RCA continues work on its compatible system; manufacturers divided as to whether to make sets and converters to receive CBS colorcasts.

October 23, 1950, RCA files suit in federal district court in Chicago asking temporary injunction against FCC's color order being made effective pending determination of suit for a permanent injunction. President of CBS Frank Stanton goes on network to "clear up" confusion over FCC color decision created by "the reaction of some of the television set manufacturers;" Robert C. Sprague, president of the Radio Television Manufacturers Association asks for and gets time to reply.

November 20, 1950 Chicago federal court issues temporary restraining order halting FCC from putting its color rule into effect before a final decision is made.

December 25, 1950 Chicago federal court dismisses RCA complaint against FCC adoption of CBS color system but bans commercial operation pending decision by U.S. Supreme Court.

March 26, 1951 FCC reveals proposed allocation plan making full use of UHF band in addition to 12 VHF channels to provide for some 2000 TV stations in more than 1200 communities. Ten percent of channels are to be reserved for "indefinite" period for non-commercial educational stations.

March 10, 1952 CBS demonstrates all-electronic color TV receiver operating with CBS color system.

April 14, 1952 FCC lifts "freeze" on TV as of July 1st. Allocations for 2053 stations in 1291 cities are assigned, 617 VHF and 1436 UHF stations, including 242 non-commercial educational stations (80 of themVHF).

June 29, 1953 RCA-NBC asks FCC to approve compatible color standards for the RCA dot-sequential color TV system on a commercial basis.

October 5, 1953 Emerson Radio & Phonograph Co. exhibits what it calls first compatible color-TV receiver; puts probable price at $700.

January 4, 1954 RCA announces first all-electronic color tube, put on market as a commercial product available ro set maufacturers.

May 9, 1960 Philco applies for channel 3 in Philadelphia, then occupied by NBC's WRCV-TV.

January 7, 1963 RCA pays Philco $9 million for patent rights; Philco withdraws bid for channel 3 Philadelphia.

FM Broadcasting The July 1, 1936 Broadcasting magazine carried this article: FM broadcasting, a new system invented by Major E. H. Armstrong, is described at FCC hearing as static-free, noise-free, free from fading and cross talk, uniform day and night throughout all seasons and with greater fidelity of reproduction.

Broadcasting magazine (February 1, 1938) FCC sets 25 channels, 40 kc wide in the 41-42 mc band for exclusive use of noncommercial, educational stations.

June 1, 1940 (Broadcasting magazine) FCC authorizes commercial operation for FM, assigns it 35 channels 200 kc wide between 43 and 50 mc; television was "put back in the laboratory until the industry reached agreement on standards."

January 16, 1945 (Broadcasting magazine) FM is moved to 84-102 mc. Advocates are disappointed because they wanted to keep it in the 50 mc area.

June 4, 1945. In a joint request FM Broadcasters Inc and Television Broadcasters Association ask FCC to allocate 44-108 mc immediately; FM to get 50-54 mc for educational use, and 54-68 mc for commercial operation. TV to receive 68-74 and 78-108 mc. But, one month later, the FCC decided to allocate 88-106 mc to FM. TV gets: channel 1, 44-50 mc; ch. 2-4, 54-72mc; ch. 5-6 76-88 mc.

January 28, 1946, After two days of hearings FCC denies petitions of Zenith and General Electric and rules that FM will stay at 88 - 108 mc.

May 10, 1948, FCC orders into effect earlier proposal assiging TV channel 1 (44-50 mc) to nongovernmental fixed and mobile services, denying FM spokesmen's pleas for that channel for use in FM network relaying; also gives FM stations in 44-50 mc band until the end of the year to move to the 88-108 mc band; issues proposed new expanded TV allocation table; calls for hearing on feasibility of TV use of frequencies above 475 mc.

July 26, 1948, Major E. H. Armstrong sues RCA and NBC for alleged infringement of five of his basic FM patents.

January 10, 1949 Resisting FCC order to move all FM to 88-108 mc, FM inventor E. H. Armstrong, wins stay order from U.S. Court of Appeals for District of Columbia permitting his experimental station W2XMN, Alpine NJ to continue operating on 44.1 mc pending a hearing.

September 28, 1950 Multiplex Development Copr., demonstrates method for similtaneous broadcast of three signals on single FM channel.

October 19, 1953 FM multiplexing system permitting simultaneous transmission of two programs on a single 200 kc FM band is demonstrated by Dr. Edwin H. Armstrong, inventor of FM.

February 8, 1954 Major Edwin Howard Armstrong, who developed FM system of broadcasting, dies at 63, a suicide.

September 21, 1959 Federal judge upholds Armstrong patents in FM, finds Emerson Radio guilty of infringement.

April 24, 1961 FCC approves FM stereophonic broadcasting.

Broadcast Day That period of time between the station's sign on and sign off.

Daytime Operation is permitted during the hours between average monthly sunrise and average monthly sunset.
The controlling times for each month of the year are stated in the station's instrument of authorization. Uniform sunrise and sunset times are specified for all days of the month, based upon the actual times of sunrise and sunset for the fifteenth day of the month adjusted to the nearest quarter hour. Sunrise and sunset times are derived by using the standardized procedure and the tables in the 1946 American Nautical Almanac issued by the United States Naval Observatory.

Video tape November 19 1951 Bing Crosby Enterprises announces development of system for recording sight-and-sound programs on magnetic tape; pictures shown at demonstration described as hazy but viewable.

January 5, 1953 Bing Crosby Enterprises demonstrates its magnetic-tape TV recordings, judged "more than 20 fold" improved over demonstration a year before.

December 7, 1953 RCA demonstrates monochrome and color-TV programs recorded on magnetic tape; General Sarnoff, RCA-NBC board chairman reports "principal elements tested and confirmed," expects two years for finishing touches needed before system is ready for market.