Clear-channel station

This article is about class A/class I protected AM stations. For stations owned by the company named Clear Channel, see Clear Channel Communications.

A clear-channel station is an AM band Radio station in North America that has the highest protection from interference from other stations, particularly concerning night-time skywave propagation. Usually known as class A stations since 1982, they are occasionally still referred to by their former classifications of class I-A, class I-B, or class I-N. The term "clear channel" is used most often in the context of North America and the Caribbean, where the concept originated.

Since 1941, these stations have been required to maintain at least 10,000 watts of power to retain their status.

Description

Certain mediumwave frequencies were set aside under the North American Radio Broadcasting Agreement (NARBA) for nighttime use by only one or two specific AM stations, covering a wide area via skywave propagation; these frequencies were known as the clear channels, and the stations on them are thus clear-channel stations. Where only one station was assigned to a clear channel, the treaty provides that it must operate with a nominal power of 50 kilowatts or more; stations on the other clear channels, with two or more stations, must use between 10 and 50 kW, and most often use a directional antenna so as not to interfere with each other. In addition to the frequencies, the treaty also specified the specific locations where stations on this second kind of channel (known as class I-B) could be built.

Some of the original NARBA signatories, including the United States, Canada, and Mexico, have implemented bilateral agreements that supersede its terms, eliminating among other things the distinction between the two kinds of clear channel: the original "I-A", "I-B", and "I-N" station classes are now all included in class A.

Clear-channel stations, unlike all other AM stations in North America, have a secondary service area—that is, they are entitled to protection from interference to their nighttime skywave signals. Other stations are entitled, at most, to protection from nighttime interference in their primary service area—that which is covered by their groundwave signal.

Many stations beyond those listed in the treaty have been assigned to operate on a clear channel (and some had been long before NARBA came into effect in 1941). In most cases, those stations operate during the daytime only, so as not to interfere with the primary stations on those channels. Since the early 1980s, many such stations have been permitted to operate at night with such low power as to be deemed not to interfere; these stations are still considered "daytimers" and are not entitled to any protection from interference to their nighttime signals. Another group of stations, formerly known as class II stations, were licensed to operate on the former "I-B" clear channels with significant power at night, provided that they use directional antenna systems to minimize radiation towards the primary stations.^{[citation needed]}

Clear Channel Communications, a San Antonio, Texas-based company which owns over 900 U.S. radio stations, was originally formed to purchase one clear-channel station, WOAI. The company now owns more than a dozen such stations^{[citation needed]}.

History

See also: Medium wave#Medium wave in the Americas

For the U.S., a form of clear channels first appeared in 1922 when the Commerce Department moved stations which had all used three (initially two) frequencies (two for entertainment stations, one for "weather and crop reports") onto 52 frequencies. Two were used for all low-power stations and the large stations each got their own frequency. A few frequencies were used on both the East and West coasts, which were considered far enough apart to limit interference. At this time large stations were limited to 1000 watts and some licences were revoked.^{[citation needed]}

On 11 November 1928, the United States implemented General Order 40, which classified each allocation in the AM band as either Local, Regional, or Clear. The classification system considered stations in Canada as well. Gradually maximum power was increased to 50,000 watts (with some short lived experiments with 250–500 kilowatt "super-power" operation). This system was continued in the 1941 NARBA system although almost all stations shifted broadcast frequencies. The FCC's intent behind licensing 50,000 watt clear channel stations was to provide reliable radio service to the thousands of Americans who lived in the vast rural areas of the United States.^[1] As a result, these stations usually reached large portions of North America at night. Radio fans often call such stations "flamethrowers" or "blowtorches" because of their power.

As early as the 1950s, debate raged in Washington, D.C., and in the U.S. broadcasting industry over whether continuation of the clear-channel system was justifiable. The licensees of clear-channel stations argued that, without their special status, many rural areas would receive no radio service at all. They requested that the power limit on the "I-A" channels in the U.S. be increased from 50 kW to 750 kW, pointing to WLW's successful experiments before the war, and in later years successful implementation by state broadcasters in Europe and the Middle East, as evidence that this would work and improve the service received by most Americans. Other broadcasters, particularly in the western states, argued to the contrary—that if the special status of the clear-channel stations were eliminated, they would be able to build new stations to provide local service to those rural "dark areas".

One station, KOB in Albuquerque, New Mexico, fought a long legal battle against the Federal Communications Commission (FCC) and New York's WABC for the right to move from a regional channel to a clear channel, 770 kHz, arguing that the New York signal was so weak in the mountain west that it served no one. KOB eventually won the argument in the late 1960s; it and several other western stations were allowed to move to eastern clear channels. (Western clear channels, like 680 in San Francisco, California, had been "duplicated" in the eastern states for many years.) These new class II-A assignments (in places like Boise, Idaho; Las Vegas and Reno, Nevada; Lexington, Nebraska; Casper, Wyoming; Kalispell, Montana; and others) began what would later be called "the breakdown of the clear channels". The class I-A station owners' proposal to increase power fifteenfold was not immediately quashed, but the new II-A stations would make it effectively impossible for stations on the duplicated channels to do so, and the owners eventually lost interest. That proposal was finally taken off the FCC's docket in the late 1970s.^{[citation needed]}

On May 29, 1980, the FCC voted to limit the protection for the twenty-five clear channel stations to a 750-mile radius around the transmitter. Those stations outside the area of protection were no longer required to sign off or power down after sundown.^[2]

In 1987 the FCC changed its rules to prohibit applications for new "class-D" stations. (Class-D stations have night power between zero and 250 watts, and frequently operate on clear channels.) However, any existing station could voluntarily relinquish nighttime authority, thereby becoming a class-D, and several have done so since the rule change.

Daytimers

Daytimers are AM radio stations that are limited to broadcasting during the daytime only, as their signals would interfere with clear channel and other radio stations at night, when solar radiation is reduced, and medium wave radio signals can propagate much farther. Such stations are usually supposed to do one of three things: sign off, reduce power (sometimes dramatically, to only a few watts), or switch to another (typically near-by) frequency.^{[citation needed]} Their broadcast class is Class D.

List of all clear-channel stations

The following two tables show all of the class-A stations in North America. First is the Canada, Mexico, and contiguous United States table, for the former class I-A and class I-B stations. Second is the Alaska table, for the former class I-N stations.

Class A (former I-A/I-B) stations

Freq. (kHz)	Callsign	City of license
540	CBK	Watrous, Saskatchewan
540	CBT	Grand Falls, Newfoundland and Labrador
540	XEWA	San Luis Potosí, San Luis Potosí
640	CBN	St. John's, Newfoundland and Labrador
640	KFI	Los Angeles, California
650	WSM	Nashville, Tennessee
660	WFAN	New York, New York
670	WSCR	Chicago, Illinois
680	KNBR	San Francisco, California
690	silent[3]	Montreal, Quebec
690	XEWW	Tijuana, Baja California
700	WLW	Cincinnati, Ohio
710	KIRO	Seattle, Washington
710	WOR	New York, New York
720	WGN	Chicago, Illinois
730	CKAC	Montreal, Quebec
730	XEX	Mexico City, D.F.
740	CFZM[4]	Toronto, Ontario
750	WSB	Atlanta, Georgia
760	WJR	Detroit, Michigan
770	WABC	New York, New York
780	WBBM	Chicago, Illinois
800	XEROK	Ciudad Juárez, Chihuahua
810	KGO	San Francisco, California
810	WGY	Schenectady, New York
820	WBAP	Fort Worth, Texas
830	WCCO	Minneapolis, Minnesota
840	WHAS	Louisville, Kentucky
850	KOA	Denver, Colorado
850	XETQ	Ixhuatlancillo, Veracruz
860	CJBC	Toronto, Ontario
870	WWL	New Orleans, Louisiana
880	WCBS	New York, New York
890	WLS	Chicago, Illinois
900	XEW	Mexico City, D.F.
940	silent[5]	Montreal, Quebec
940	XEQ	Mexico City, D.F.
990	CBW	Winnipeg, Manitoba
990	CBY	Corner Brook, Newfoundland and Labrador
1000	KOMO	Seattle, Washington
1000	WMVP	Chicago, Illinois
1000	XEOY	Mexico City, D.F.
1010	CBR	Calgary, Alberta
1010	CFRB	Toronto, Ontario
1020	KDKA	Pittsburgh, Pennsylvania
1030	WBZ	Boston, Massachusetts
1040	WHO	Des Moines, Iowa
1050	XEG	Monterrey, Nuevo León
1060	KYW	Philadelphia, Pennsylvania
1060	XEEP	Mexico City, D.F.
1070	silent[6]	Moncton, New Brunswick
1070	KNX	Los Angeles, California
1080	WTIC	Hartford, Connecticut
1080	KRLD	Dallas, Texas
1090	KAAY	Little Rock, Arkansas
1090	WBAL	Baltimore, Maryland
1090	XEPRS	Rancho del Mar, Rosarito, Baja California
1100	WTAM	Cleveland, Ohio
1110	KFAB	Omaha, Nebraska
1110	WBT	Charlotte, North Carolina
1120	KMOX	St. Louis, Missouri
1130	CKWX	Vancouver, British Columbia
1130	KWKH	Shreveport, Louisiana
1130	WBBR	New York, New York
1140	WRVA	Richmond, Virginia
1140	XEMR	Monterrey, Nuevo León
1160	KSL	Salt Lake City, Utah
1170	KFAQ	Tulsa, Oklahoma
1170	WWVA	Wheeling, West Virginia
1180	WHAM	Rochester, New York
1190	KEX	Portland, Oregon
1190	XEWK	Guadalajara, Jalisco
1200	WOAI	San Antonio, Texas
1210	WPHT	Philadelphia, Pennsylvania
1220	XEB	Mexico City, D.F.
1500	KSTP	Saint Paul, Minnesota
1500	WFED	Washington, D.C.
1510	WLAC	Nashville, Tennessee
1520	KOKC	Oklahoma City, Oklahoma
1520	WWKB	Buffalo, New York
1530	KFBK	Sacramento, California
1530	WCKY	Cincinnati, Ohio
1540	KXEL	Waterloo, Iowa
1540	ZNS-1	Nassau, Bahamas
1550	CBE	Windsor, Ontario
1550	XERUV	Xalapa, Veracruz
1560	KNZR[7]	Bakersfield, California
1560	WQEW	New York, New York
1570	XERF	Ciudad Acuña, Coahuila
1580	CKDO[8]	Oshawa, Ontario

Alaskan class A (former class I-N) stations

Freq. (kHz)	Callsign	City of license
640	KYUK	Bethel
650	KENI	Anchorage
660	KFAR	Fairbanks
670	KDLG	Dillingham
680	KBRW	Barrow
700	KBYR	Anchorage
720	KOTZ	Kotzebue
750	KFQD	Anchorage
770	KCHU	Valdez
780	KNOM	Nome
820	KCBF	Fairbanks
850	KICY	Nome
890	KBBI	Homer
1020	KOAN	Eagle River
1080	KUDO	Anchorage
1170	KJNP	North Pole

List of former clear-channel stations

Frequency (kHz)	Callsign	City of license	Fate
1190	WOWO	Fort Wayne, Indiana	Downgraded to class B in 1998 by reducing night power to 9.8 kW
1510	KGA	Spokane, Washington	Downgraded to class B in 2011 to make room for co-channel sister station KSFN, Piedmont, California, reducing night power to 15 kW[9]

Notes

1. ^ Rural Radio Magazine, Vol. 1 No. 1, Clear Channel Group (November 1938), p. 2
2. ^ Facts on File 1980 Yearbook, p519
3. ^ 690 kHz at Montreal was originally assigned under NARBA to CBF, and was later reused by CINF; while now silent, it remains notified to the U.S. as a class-A allotment.
4. ^ 740 kHz was used by CBC Radio One's CBL in Toronto until 2000 when the station moved to 99.1 FM. CFZM, known at the time as CHWO, acquired 740 in 2001.
5. ^ 940 kHz at Montreal was originally assigned under NARBA to CBM, and was later reused by CINW; while now silent, it remains notified to the U.S. as a class-A allotment.
6. ^ 1070 kHz was formerly used by CBA, which moved to FM in April, 2008. Canada has not withdrawn the international notification for CBA.
7. ^ KNZR is the only U.S. class-A station licensed to operate with less than 50 kilowatts full-time; KNZR is licensed for 25 kW during the day and 10 kW at night.
8. ^ 1580 kHz was originally used by CBJ in Chicoutimi, Quebec. After that station moved to FM in 1999, CHUC applied for and was granted 1580 kHz in Cobourg, Ontario with 10 kW, but chose instead to move to FM itself (despite being notified to the U.S. as an existing station on 1580). CKDO moved from 1350 to 1580 kHz on August 13, 2006 and became that day a class A station using 10 kW. U.S. FCC record is at [1]
9. ^ FCC license BL-20100527AGH

See also

• Canadian allocations changes under NARBA
• Clear Channel Communications
• Daytimer

External links

• AM Station Classes - Clear, Regional, and Local Channels (FCC Website)
• Big USA, Mexico, and Canadian AM radio stations