List of North American broadcast station classes
This is a list of broadcast station classes applicable in much of North America under international agreements between the United States, Canada and Mexico. Effective radiated power and height above average terrain are listed unless otherwise noted.
All radio and television stations within 320 kilometers of the US-Canada or US-Mexico border must get approval by both the domestic and foreign agency. These agencies are Industry Canada/Canadian Radio-television and Telecommunications Commission in Canada, the Federal Communications Commission in the US, and the Federal Telecommunications Institute in Mexico.
AM
Station class descriptions
All domestic AM stations are classified as A, B, C, or D.- A — clear-channel stations — 10 kW to 50 kW, 24 hours.
- *Class A stations are only protected within a 750-mile radius of the transmitter site.
- *The old Class I was divided into three: Class I-A, I-B and I-N. NARBA distinguished between Class I-A, which were true clear-channel stations that did not share their channel with another Class I station, and Class I-B, in which a station operated with 50 kW at night but shared its channel with at least one other I-B station, requiring directional operation. This distinction was superseded by the Rio Agreement, which instituted the current class system.
- *Most former Class I-As are omnidirectional, though some exceptions exist and some formerly operated directional arrays.
- *Most former Class I-Bs are directional at night, although a few are also directional during days.
- *A very few former Class I-As who dropped to Class I-B while retaining their I-A facilities operate omnidirectionally during all hours.
- *Former Class I-N stations exist only in Alaska, where they are too remote to interfere with other clear-channel stations. They are only held to Class B efficiency standards.
- *No new Class A stations are licensed in the conterminous United States, although the FCC states it may be possible to license additional Class A stations in Alaska.
- B — regional stations — 250 W to 50 kW, 24 hours.
- *Stations on the AM expanded band, 1610 kHz to 1700 kHz, are limited to 10 kW days and 1 kW nights, non-directionally.
- *Several expanded band stations operate DA-N or even DA-2 with up to 10 kW during all hours, after providing proof that such operations will not cause co- or adjacent-channel interference.
- *If under 250 W at night, the antenna must be efficient enough to radiate more than 140.82 mV/m at 1 km.
- C — local unlimited-time stations — 250 W to 1 kW, 24 hours.
- *Class C stations that were licensed at 100 W are grandfathered.
- *Rare Class Cs operate with directional arrays, such as KYPA and KHCB.
- D — current and former daytimers — Daytime 250 W to 50 kW, nighttime under 250 W or off-air.
- *Field strength is limited to 140 mV/m at 1 km.
- *No new class D stations are licensed, with the exception of Class B stations that are downgrading their nighttime operations to Class D. The station's daytime operation is then also reclassified as Class D.
- *If a Class D station is on the air at night, it is not protected from any co-channel interference.
- TIS/HAR — travelers' information stations / highway advisory radio stations — Up to 10 W transmitter output power. Stations within US national parks are licensed by NTIA and not the FCC.
- Unlicensed broadcasting — — 100 mW DC input to final amplifier with a 3-meter maximum length radiator, no license needed, may be measured at edge of campus for school stations
- In the Western Hemisphere, medium wave AM broadcasts are on channels spaced 10 kHz apart from 530 kHz to 1700 kHz, with certain classes restricted to subsets of the available frequencies.
- With few exceptions, Class A stations can be found only on the frequencies of 540 kHz, 640 to 780 kHz, 800 to 900 kHz, 940 kHz, 990 to 1140 kHz, 1160 to 1220 kHz, and 1500 to 1580 kHz. The exceptions are cited in relevant international treaties.
- While US and Canadian Class A stations are authorized to operate at a maximum of 50,000 watts day and night, certain existing Mexican Class A stations, and certain new Cuban Class A stations are authorized to operate at a higher power. Certain Mexican Class A stations are authorized to operate at less than 50,000 watts at night, if grandfathered, but may operate at up to 100,000 watts during the day.
- Class B and D stations can be found on any frequencies from 540 kHz to 1700 kHz except where frequencies have been reserved for Class C stations.
- Class C stations can be found in the lower 48 US states on the frequencies of 1230 kHz, 1240 kHz, 1340 kHz, 1400 kHz, 1450 kHz, and 1490 kHz. Other countries may use other frequencies for their Class C stations.
- American territories in ITU region 3 with AM broadcasting stations use the 9 kHz spacing customary to the rest of the world. All stations are class B or lower.
- Canada also defines Class CC and LP.
- TIS stations can be found on any frequency from 530 kHz to 1700 kHz in the US, but may only carry non-commercial messages without music. There is a network of TISs on 1710 in New Jersey.
- Low-power AM stations located on a school campus are allowed to be more powerful, so long as their signal strength does not exceed roughly 14 to 45 µV/m at a distance of 30 meters from campus.
Former system
The following conversion table compares the old AM station classes with the new AM station classes:
AM station classes and clear channels listed by frequency
The following chart lists frequencies on the broacast company band, and which classes broadcast on these frequencies; Class A and Class B, 10,000 watt and higher stations in North America which broadcast on clear-channel station frequencies are also shown.By international agreement, Class A stations must be 10,000 watts and above, with a 50,000 watt maximum for the US and Canada, but no maximum for other governments in the region. Mexico, for example, typically runs 150,000 to 500,000 watts, but some stations are grandfathered at 10,000 to 20,000 watts at night; by treaty, these sub-50,000 watt Mexican stations may operate with a maximum of 100,000 watts during the daytime.
Because the AM broadcast band developed before technology suitable for directional antennas, there are numerous exceptions, such as the US use of 800 and 900 non-directionally in Alaska, limited to 5 kW at night; and 1050 and 1220, directionally, in the continental US, and without time limits; each of these being assigned to specific cities. In return for these limits on US stations, Mexico accepted limits on 830 and 1030 in Mexico City, non-directionally, restricted to 5 kW at night.
| Channel Type | Frequency | Available Classes | Assignment Old class designation in |
| — | 530 | — | In the US, reserved for low power AM Travelers' Information Stations |
| Clear | 540 | A, B, D | CBK Watrous, Saskatchewan: Class A CBT Grand Falls-Windsor, Newfoundland and Labrador: Class A XEWA San Luis Potosí, San Luis Potosí: Class A WFLF Pine Hills, Florida: Class B |
| Regional | 550 | , B, D | CMBV Wajay, Cuba: Class A |
| Regional | 560 | B, D | |
| Regional | 570 | , B, D | CMEA Santa Clara, Cuba: Class A |
| Regional | 580 | , B, D | CMAA Pinar del Rio, Cuba: Class A |
| Regional | 590 | , B, D | CMCA San Antonio Vegas, Cuba: Class A |
| Regional | 600 | , B, D | CMKA San German, Cuba: Class A |
| Regional | 610 | B, D | |
| Regional | 620 | , B, D | CMDA Colon, Cuba: Class A |
| Regional | 630 | , B, D | CMHA Camaguey, Cuba: Class A |
| Clear | 640 | A, B, D | KFI Los Angeles, California: Class A KYUK Bethel, Alaska: Class A CBN St. John's, Newfoundland and Labrador: Class A |
| Clear | 650 | A, B, D | WSM Nashville, Tennessee: Class A KENI Anchorage, Alaska: Class A |
| Clear | 660 | A, B, D | WFAN New York City: Class A KFAR Fairbanks, Alaska: Class A KTNN Window Rock, Arizona: Class B CMDC Colon, Cuba: Class A |
| Clear | 670 | A, B, D | WSCR Chicago, Illinois: Class A KDLG Dillingham, Alaska: Class A KBOI Boise, Idaho: Class B CMBC Arroyo Arena, Cuba: Class A |
| Clear | 680 | A, B, D | KNBR San Francisco, California: Class A ND-U KBRW Barrow, Alaska: Class A WRKO Boston, Massachusetts: Class B WCBM Baltimore, Maryland: Class B WPTF Raleigh, North Carolina: Class B |
| Clear | 690 | A, B, D | CKGM Montreal, Quebec: Class A CBU Vancouver, British Columbia: Class B XEWW Tijuana, Baja California: Class A WOKV Jacksonville, Florida: Class B CMEC Santa Clara, Cuba: Class A |
| Clear | 700 | A, B, D | WLW Cincinnati, Ohio: Class A KBYR Anchorage, Alaska: Class A |
| Clear | 710 | A, B, D | WOR New York City: Class A KIRO Seattle, Washington: Class A KSPN Los Angeles, California: Class B WAQI Miami, Florida: Class B |
| Clear | 720 | A, B, D | WGN Chicago, Illinois: Class A KOTZ Kotzebue, Alaska: Class A KDWN Las Vegas, Nevada: Class B |
| Clear | 730 | A, B, D | CKAC Montreal, Quebec: Class A XEX Mexico City: Class A CMHC Camaguey, Cuba: Class A |
| Clear | 740 | A, B, D | CFZM Toronto, Ontario: Class A KCBS San Francisco, California: Class B WYGM Orlando, Florida: Class B KRMG Tulsa, Oklahoma: Class B KTRH Houston, Texas: Class B CMAC Pinar del Rio, Cuba: Class A |
| Clear | 750 | A, B, D | WSB Atlanta, Georgia: Class A KFQD Anchorage, Alaska: Class A CBGY Bonavista, Newfoundland and Labrador: Class A KMMJ Grand Island, Nebraska: Class B KXTG Portland, Oregon: Class B |
| Clear | 760 | A, B, D | WJR Detroit, Michigan: Class A KGB San Diego, California: Class B CMKC Cacocun, Cuba: Class A |
| Clear | 770 | A, B, D | WABC New York City: Class A KKOB Albuquerque, New Mexico: Class B KCHU Valdez, Alaska: Class A KTTH Seattle, Washington: Class B |
| Clear | 780 | A, B, D | WBBM Chicago, Illinois: Class A KNOM Nome, Alaska: Class A KKOH Reno, Nevada: Class B |
| Regional | 790 | , B, D | CMAC Guanabacoba, Cuba: Class A |
| Clear | 800 | A, B, D | XEROK Ciudad Juárez, Chihuahua: Class A CKLW Windsor, Ontario: Class B CMEB Santa Clara, Cuba: Class A |
| Clear | 810 | A, B, D | KGO San Francisco, California: Class A WGY Schenectady, New York: Class A ND-U, but KGO was the originally assigned dominant station WHB Kansas City, Missouri: Class B WKVM San Juan, Puerto Rico: Class B |
| Clear | 820 | A, B, D | WBAP Fort Worth, Texas: Class A KCBF Fairbanks, Alaska: Class A |
| Clear | 830 | A, B, D | WCCO Minneapolis, Minnesota: Class A KLAA Orange, California: Class B XEITE Mexico City, Mexico: Class B |
| Clear | 840 | A, B, D | WHAS Louisville, Kentucky: Class A KXNT North Las Vegas, Nevada: Class B |
| Clear | 850 | A, B, D | KOA Denver, Colorado: Class A ND-U KICY Nome, Alaska: Class A WEEI Boston, Massachusetts: Class B WTAR Norfolk, Virginia: Class B |
| Clear | 860 | A, B, D | CJBC Toronto, Ontario: Class A KTRB San Francisco, California: Class B Presently operating at 7.5 kW nights CMDB Colon, Cuba: Class A |
| Clear | 870 | A, B, D | WWL New Orleans, Louisiana: Class A |
| Clear | 880 | A, B, D | WCBS New York City: Class A KRVN Lexington, Nebraska: Class B CMAB Pinar del Rio, Cuba: Class A |
| Clear | 890 | A, B, D | WLS Chicago, Illinois: Class A KBBI Homer, Alaska: Class A KDXU St. George, Utah: Class B CMHB Camaguey, Cuba: Class A |
| Clear | 900 | A, B, D | XEW Mexico City: Class A CKBI Prince Albert, Saskatchewan: Class A CMKB Cacocun, Cuba: Class A |
| Regional | 910 | , B, D | CMAC Guanabacoba, Cuba: Class A |
| Regional | 920 | B, D | |
| Regional | 930 | B, D | |
| Clear | 940 | A, B, D | CINW Montreal, Quebec: Class A XEQ Mexico City: Class A ND-U KFIG Fresno, California: Class B |
| Regional | 950 | B, D | KJR Seattle, Washington Class B WWJ Detroit, Michigan: Class B |
| Regional | 960 | B, D | |
| Regional | 970 | B, D | |
| Regional | 980 | B, D | |
| Clear | 990 | A, B, D | CBW Winnipeg, Manitoba: Class A CBY Corner Brook, Newfoundland and Labrador: Class A WTLN Orlando, Florida: Class B |
| Clear | 1000 | A, B, D | WMVP Chicago, Illinois: Class A KOMO Seattle, Washington: Class A XEOY Mexico City, Mexico: Class A |
| Clear | 1010 | A, B, D | CBR Calgary, Alberta: Class A CFRB Toronto, Ontario: Class A WINS New York City: Class B CMBX Wajay, Cuba: Class A |
| Clear | 1020 | A, B, D | KDKA Pittsburgh, Pennsylvania: Class A KVNT Eagle River, Alaska: Class A KCKN Roswell, New Mexico: Class B KTNQ Los Angeles, California: Class B |
| Clear | 1030 | A, B, D | WBZ Boston, Massachusetts: Class A KTWO Casper, Wyoming: Class B XEQR Mexico City, Mexico: Class B |
| Clear | 1040 | A, B, D | WHO Des Moines, Iowa: Class A |
| Clear | 1050 | A, B, D | CHUM Toronto, Ontario: Class B XEG Guadalupe, Nuevo León: Class A WEPN New York City: Class B |
| Clear | 1060 | A, B, D | KYW Philadelphia, Pennsylvania: Class A XEEP Mexico City: Class A |
| Clear | 1070 | A, B, D | KNX Los Angeles, California: Class A ND-U CBA Moncton, New Brunswick: Class A ND-U |
| Clear | 1080 | A, B, D | WTIC Hartford, Connecticut: Class A KRLD Dallas, Texas: Class A KOAN Anchorage, Alaska: Class A KFXX Portland, Oregon: Class B |
| Clear | 1090 | A, B, D | KAAY Little Rock, Arkansas: Class A WBAL Baltimore, Maryland: Class A XEPRS Rosarito Beach, Baja California: Class A KFNQ Seattle, Washington: Class B |
| Clear | 1100 | A, B, D | WTAM Cleveland, Ohio: Class A KNZZ Grand Junction, Colorado: Class B KFAX San Francisco, California: Class B |
| Clear | 1110 | A, B, D | WBT Charlotte, North Carolina: Class A KFAB Omaha, Nebraska: Class A KRDC Pasadena, California: Class B |
| Clear | 1120 | A, B, D | KMOX St. Louis, Missouri: Class A KPNW Eugene, Oregon: Class B |
| Clear | 1130 | A, B, D | KWKH Shreveport, Louisiana: Class A WBBR New York City: Class A CKWX Vancouver, British Columbia: Class A KTLK Minneapolis, Minnesota: Class B |
| Clear | 1140 | A, B, D | WRVA Richmond, Virginia: Class A XEMR Apodaca, Nuevo León: Class A KHTK Sacramento, California: Class B |
| Regional | 1150 | B, D | |
| Clear | 1160 | A, B, D | KSL Salt Lake City, Utah: Class A WYLL Chicago, Illinois: Class B |
| Clear | 1170 | A, B, D | KFAQ Tulsa, Oklahoma: Class A WWVA Wheeling, West Virginia: Class A KJNP North Pole, Alaska: Class A |
| Clear | 1180 | A, B, D | WHAM Rochester, New York: Class A KOFI Kalispell, Montana: Class B |
| Clear | 1190 | A, B, D | KEX Portland, Oregon: Class A WOWO Fort Wayne, Indiana: Class B WLIB New York City: Class B XEWK-AM Guadalajara, Jalisco, Mexico: Class A |
| Clear | 1200 | A, B, D | WOAI San Antonio, Texas: Class A WMUZ Taylor, Michigan: Class B |
| Clear | 1210 | A, B, D | WPHT Philadelphia, Pennsylvania: Class A KGYN Guymon, Oklahoma: Class B |
| Clear | 1220 | A, B, D | XEB Mexico City: Class A WHKW Cleveland, Ohio: Class B |
| Regional | 1230 | B | Stations in Alaska, Hawaii, Puerto Rico, and the United States Virgin Islands |
| Local | 1230 | C | Stations in conterminous 48 states |
| Regional | 1240 | B | Stations in Alaska, Hawaii, Puerto Rico, and the United States Virgin Islands |
| Local | 1240 | C | Stations in conterminous 48 states |
| Regional | 1250 | B, D | |
| Regional | 1260 | B, D | CFRN Edmonton, Alberta: Class A |
| Regional | 1270 | B, D | |
| Regional | 1280 | B, D | |
| Regional | 1290 | B, D | |
| Regional | 1300 | B, D | |
| Regional | 1310 | B, D | |
| Regional | 1320 | B, D | |
| Regional | 1330 | B, D | |
| Regional | 1340 | B | Stations in Alaska, Hawaii, Puerto Rico, and the United States Virgin Islands |
| Local | 1340 | C | Stations in conterminous 48 states |
| Regional | 1350 | B, D | |
| Regional | 1360 | B, D | |
| Regional | 1370 | B, D | |
| Regional | 1380 | B, D | KRKO Everett, Washington Class B |
| Regional | 1390 | B, D | |
| Regional | 1400 | B | Stations in Alaska, Hawaii, Puerto Rico, and the United States Virgin Islands |
| Local | 1400 | C | Stations in conterminous 48 states |
| Regional | 1410 | B, D | |
| Regional | 1420 | B, D | |
| Regional | 1430 | B, D | |
| Regional | 1440 | B, D | |
| Regional | 1450 | B | Stations in Alaska, Hawaii, Puerto Rico, and the United States Virgin Islands |
| Local | 1450 | C | Stations in conterminous 48 states |
| Regional | 1460 | B, D | |
| Regional | 1470 | B, D | |
| Regional | 1480 | B, D | |
| Regional | 1490 | B | Stations in Alaska, Hawaii, Puerto Rico, and the United States Virgin Islands |
| Local | 1490 | C | Stations in conterminous 48 states |
| Clear | 1500 | A, B, D | WFED Washington, D.C.: Class A KSTP Saint Paul, Minnesota: Class A |
| Clear | 1510 | A, B, D | WLAC Nashville, Tennessee: Class A WMEX Boston, Massachusetts: Class B KGA Spokane, Washington: Class B |
| Clear | 1520 | A, B, D | WWKB Buffalo, New York: Class A KOKC Oklahoma City, Oklahoma: Class A KQRR Oregon City, Oregon: Class B KKXA Snohomish, Washington Class B |
| Clear | 1530 | A, B, D | KFBK Sacramento, California: Class A WCKY Cincinnati, Ohio: Class A |
| Clear | 1540 | A, B, D | KXEL Waterloo, Iowa: Class A ZNS-1 Nassau, Bahamas: Class A KMPC Los Angeles, California: Class B |
| Clear | 1550 | A, B, D | XERUV Xalapa, Veracruz: Class A CBEF Windsor, Ontario: Class A KKOV Vancouver, Washington: Class B |
| Clear | 1560 | A, B, D | KNZR Bakersfield, California: Class A Only US Class A grandfathered at 10 kW nights WFME New York City: Class A |
| Clear | 1570 | A, B, D | XERF Ciudad Acuña, Coahuila: Class A |
| Clear | 1580 | A, B, D | CKDO Oshawa, Ontario: Class A KBLA Santa Monica, California: Class B |
| Regional | 1590 | B, D | |
| Regional | 1600 | B, D | |
| Regional | 1610 | In the US, used solely by low power AM Travelers' Information Stations. | |
| Regional | 1620 | B | |
| Regional | 1630 | B | |
| Regional | 1640 | B | |
| Regional | 1650 | B | |
| Regional | 1660 | B | |
| Regional | 1670 | B | |
| Regional | 1680 | B | |
| Regional | 1690 | B | |
| Regional | 1700 | B |
FM
Station class description
| Class | Effective Radiated Power | Antenna Height Above Average Terrain | Reference distance |
| C | 100 kW | 300 m to 600 m | 91.8 km |
| C0 | 100 kW | 300 m to 450 m | 83.4 km |
| C1 | up to 100 kW | under 300 m | 72.3 km |
| C2 | up to 50 kW | up to 150 m | 52.2 km |
| C3 | up to 25 kW | up to 100 m | 39.1 km |
| C4 | up to 12 kW | up to 100 m | 33.3 km |
| B | up to 50 kW | up to 150 m | 65.1 km |
| B1 | up to 25 kW | up to 100 m | 44.7 km |
| A | 100 W to 6 kW | up to 100 m | 28.3 km |
| AA | up to 6 kW | up to 100 m | 28 km |
| D | up to 250 W ERP except US non-translators to 10W TPO up to 50 W | unlimited up to 45 m | unspecified 5 km |
| L1 | 50 W to 100 W | up to 30 m | 5.6 km |
| L2 | 1 W to 10 W | up to 30 m | 3.2 km |
| LP | 10-50 W | ||
| VLP | up to 10 W | ||
| unlicensed | signal strength of 250 µV/m, 100 µV/m | unspecified | measured at 3 m, 30 m |
Notes:
- Canada protects all radio stations out to a signal strength of 0.5mV/m, whereas only commercial B stations in the US are. Commercial B1 in the US is 0.7mV/m, and all other stations are 1.0mV/m. Noncommercial-band stations are not afforded this protection, and are treated as C3 and C2 even when they are B1 or B. C3 and C2 may also be reported internationally as B1 and B, respectively.
- Class C0 is for former C stations, demoted at request of another station which needs the downgrade to accommodate its own facilities.
- In practice, many stations are above the maximum HAAT for a particular class, and correspondingly must downgrade their power to remain below the reference distance. Conversely, they may not increase power if they are below maximum HAAT.
- All class D stations are secondary in the US, and can be bumped or forced off-air completely, even if they are not just a repeater and are the only station a licensee has.
- The United States is divided into regions that have different restrictions for FM stations. Zone I and I-A is limited to classes B and B1, while Zone II has only the C classes. All areas have the same classes for A and D.
- Power and height restrictions were put in place in 1962. A number of previously existing stations were grandfathered in, such as KVYB in Santa Barbara, California and WMC-FM in Memphis, Tennessee.
| FM station class | Reference facilities for station class | FM protected or primary service contour | Distance to protected or primary service contour | Distance to 70 dBu city-grade or principal community coverage contour |
| Class A | 6 kW | 60 dBu | ||
| Class B1 | 25 kW | 57 dBu | ||
| Class B | 50 kW | 54 dBu | ||
| Class C3 | 25 kW | 60 dBu | ||
| Class C2 | 50 kW | 60 dBu | ||
| Class C1 | 100 kW | 60 dBu | ||
| Class C0 | 100 kW | 60 dBu | ||
| Class C | 100 kW | 60 dBu |
Historically, there were local "Class A" frequencies to which only class A stations would be allocated & the other frequencies could not have a class A. According to the 1982 FCC rules & regulations, those frequencies were: 92.1, 92.7, 93.5, 94.3, 95.3, 95.9, 96.7, 97.7, 98.3, 99.3, 100.1, 100.9, 101.7, 102.3, 103.1, 103.9, 104.9, 105.5, 106.3 & 107.1. Stations on those twenty frequencies were limited to having equivalent signals no greater that 3KW at 300 feet above average terrain.
FM zones
The US is divided into three zones for FM broadcasting: I, I-A and II. The zone where a station is located may limit the choices of broadcast class available to a given FM station.Zone I in the US includes all of Connecticut, the District of Columbia, Delaware, Illinois, Indiana, Massachusetts, Maryland, New Jersey, Ohio, Pennsylvania, Rhode Island, and West Virginia. It also includes the areas south of latitude 43.5°N in Michigan, New Hampshire, New York, and Vermont; as well as coastal Maine, southeastern Wisconsin, and northern and eastern Virginia.
Zone I-A includes California south of 40°N, as well as Puerto Rico and the US Virgin Islands.
Zone II includes the remainder of the continental US, plus Alaska and Hawaii.
In Zones I and I-A, there are no Class C, C0, or C1 stations. However, there are a few Class B stations with grandfathered power limits in excess of 50 KW, such as WETA, WNCI, KPFK, and the most extreme example being WBCT.
TV
Full-power stations in the US
- VHF low : 100 kW video analog at 1,000 feet in Zone I and 2,000 feet in Zone II and Zone III above average terrain; 10 kW in Zone I and 45 kW in Zone II and Zone III digital at 1,000 feet above average terrain
- VHF high : 316 kW video analog at 1,000 feet in Zone I and 2,000 feet in Zone II and Zone III above average terrain; 30 kW in Zone I and 160 kW in Zone II and Zone III digital at 1,000 feet above average terrain
- UHF: video analog at 2,000 feet above average terrain; digital at 2,000 feet above average terrain
All full-power analog television station transmissions in the US were terminated at midnight Eastern Daylight Time on June 12, 2009. Many broadcasters replaced their analog signal with their digital ATSC signal on the same transmission channel at that time.
- All US digital stations received a -DT suffix during the analog-to-digital transition. At analog shutdown, the FCC assigned to each digital station the call sign its associated analog station had used. . Stations could optionally choose to keep the -DT suffix. Most stations did not keep the -DT suffix.
- For US analog stations, the -TV suffix was required if there was a radio station with the same three- or four-letter callsign. Stations not required to use the -TV suffix may optionally request it if desired.
- Analog audio power was limited to 22% of video.
Full-power stations in Canada
- Class A: UHF, 10 kW video/100m EHAAT
- Class B: UHF, 100 kW video/150m EHAAT
- Class C: UHF, video/300m EHAAT
- Class D: UHF, more than /300m EHAAT
- Class R: VHF, 100 kW low-band, 325 kW high-band.
- Class S: VHF, more than 100 kW low-band/325 kW high-band.
- Official definitions of these classes are difficult to locate. The values above are inferred from the . There is some ambiguity about the difference between Classes C and D.
- Power-level limitations are not firmly enforced in Canada, and Industry Canada has been known to license stations for power levels much higher than the generally accepted limits. For example, CFRN-TV in Edmonton, Alberta operated on Channel 3 at over 600 kW but was not subject to international co-ordination due to its location 500 km north of the border.
- In Canada, the callsigns of all private TV stations have the -TV suffix. Most CBC Television and Ici Radio-Canada Télé TV callsigns end in the letter T and have no suffix. A few Radio-Canada stations, purchased by the CBC from private owners, retain the old -TV callsigns.
- Canadian digital stations all receive the -DT suffix. The shows -PT suffixes for the channel allotments for permanent post-transition digital operation but when licences are issued for these permanent digital stations, -DT callsigns are used.
Low-power TV (US)
- VHF: 3 kW analog video; 3 kW digital
- UHF: 150 kW analog video; 15 kW digital
- Experimental
- Unlicensed: not allowed except for medical telemetry, and certain wireless microphones
Broadcast translators, boosters, and other LPTV stations are considered secondary to full-power stations, unless they have upgraded to class A. Class A is still considered LPTV with respect to stations in Canada and Mexico.
Class A television (US)
Class-A stations :- VHF: 3 kW analog video; 3 kW digital
- UHF: 150 kW analog video; 15 kW digital
Additionally, class-A stations, LPTV stations, and translators are the only stations currently authorized to broadcast both analog and digital signals, unlike full-power stations which must broadcast a digital signal only.
Low-power TV (Canada)
In Canada, there is no formal transmission power below which, a television transmitter is considered broadcasting at low power. Industry Canada considers that a low power digital television undertaking "shall not normally extend a distance of 20 km in any direction from the antenna site," based on the determined noise-limited bounding contour.Mexico
All digital television stations in Mexico have -TDT callsign suffixes. Analog stations, which existed until December 31, 2016, had -TV callsign suffixes.The equivalent of low power or translator service in Mexico is the equipo complementario de zona de sombra, which is intended only to fill in gaps between a station's expected and actual service area caused by terrain; a station of this type shares the callsign of another station. In analog, these services often were broadcast on the same or adjacent channels to their parent station, except in certain areas with tight packing of television stations. In digital, these services usually operate on the same RF channel as their parent station, except for those with conflicting full-power applications, in certain other cases where it is technically not feasible or to make way for eventual repacking on upper UHF.
Equipos complementarios can relay their parent station, or a station that carries 75% or more of the same programming as its parent station.
Stations of either type may have unusually low or high effective radiated powers. XHSMI-TDT in Oaxaca is licensed for two watts in digital. The highest-powered shadows are XEQ-TDT Toluca and XHBS-TDT Ciudad Obregón, both at 200 kW.
FCC service table
The United States Federal Communications Commission lists the following services on their website for television broadcasting:| Broadcast class | Service | Suffixes used or call sign examples |
| Television allotment | TA | An allocation of a frequency to a city of license for which no corresponding call sign or license has been assigned. FCC placeholder for possible future construction permits or frequencies allocated to non-US broadcast use. No call sign, identifier is a date followed by a sequential two-letter value in the US FCC database. |
| Full-service TV | TV | -TV or none Since the shutdown of all full power analog stations in June 2009, used only for historical records. |
| Class A | CA | -CA, or a translator-style call sign |
| Low-power station or translator | LP | -LP, or a translator-style call sign |
| TV boosters | TB | Rare. These use the parent station's call sign plus a sequential number, such as WSTE1, WSTE2, WSTE3. Nameplates for on-channel repeaters bear the parent station's call sign, followed by "booster". See distributed transmission. If the station is digital, and has on-channel boosters, they would typically be named WSTE-DT1, WSTE-DT2, WSTE-DT3 and so on. |
| TV auxiliary service | TS | no specific suffix |
| NTSC petition for a channel change | NN | no specific suffix; uses same call sign as the station which made a request for a number/channel change. |
| Digital Television | DT | -DT, -TV or none. Some stations formerly used -HD, but this has become obsolete. The -DT suffix, optional for digital-only stations, was used primarily to distinguish a DTV transmission from an analog signal of the same broadcast ; likewise, -TV is optional except if the eponymous radio stations exist. A similar suffix -DTV, is used on all television stations in Japan. |
| Digital Class-A | CD | -CD Some stations briefly used -DC as well. A scant few still use translator-style call signs with the -D suffix. |
| Digital Low-power | LD | -LD or translator-style calls with -D suffix, occasionally no suffix. Some stations briefly used -DL as well. Some full-powered stations have been granted approval for fill-in translators within their broadcast market to better cover outlying towns or heavily urbanied areas, particularly by stations with a VHF digital signal. These are technically -LD stations, but have the same call-sign as their parent station, similar to a Distributed Transmission System. |
| Digital special temporary authority | DS | no specific suffix; uses same call sign as station making a request for permission from the FCC to use a channel, power level or transmitter location not permanently allocated for one particular station. Temporary assignments retain, unmodified, the call sign of the corresponding permanent allocation; this includes translator-style calls even on those temporarily moving to another frequency. |
| Digital Television distributed transmission system | DD | no specific suffix ; this is usually requested for a single-frequency network and to tailor coverage area to the needs of the viewers in the station's service area |
| Digital auxiliary service | DX | no specific suffix |
| Digital rulemaking petition | DR | no specific suffix; uses same call sign as station making this request to add or modify a digital channel allocation |
| Land mobile use of a TV channel | LM | As "LM" is used in the FCC database to indicate reallocation of an entire channel, but not to identify individual users transmitting in that spectrum, a 6 MHz LM allocation does not itself carry a TV-style call sign. The spectrum of TV channels 14-20 is called "T-band" in LMR use. Repeaters that operate in such an allocation use a 3 MHz offset instead of 5 MHz as normally used in the 450-470 MHz range. |
| ATSC 3.0 Futurecast Experimental Broadcasts | EX | Used for officially licensed experimental 4K/2160p Ultra HDTV broadcast stations, such as WRAL-TV's UHDTV simulcast, WRAL-EX. |