Types of radio emissions

The bandwidth (BBBB above) is expressed as four characters: three digits and one letter. The letter occupies the position normally used for a decimal point, and indicates what unit of frequency is used to express the bandwidth. The letter H indicates Hertz, K indicates kiloHertz, M indicates megaHertz, and G indicates gigaHertz. For instance, "500H" means 500 Hz, and "2M50" means 2.5 MHz. The first character must be a digit between 1 and 9 or the letter H; it may not be the digit 0 or any other letter.[1]

Types 4 and 5 were removed from use with the 1982 Radio Regulations. In previous editions, they had indicated facsimile and video, respectively.

A3E or A3E G

Ordinary amplitude modulation used for low frequency and medium frequency AM broadcasting

A8E, A8E H

AM stereo broadcasting.

F8E, F8E H

FM broadcasting for radio transmissions on VHF, and as the audio component of analogue television transmissions. Since there are generally pilot tones (subcarriers) for stereo and RDS the designator '8' is used, to indicate multiple signals.

C3F, C3F N

Analogue PAL, SÉCAM, or NTSC television video signals (formerly type A5C, until 1982)

C7W

ATSC digital television, commonly on VHF or UHF

G7W

DVB-T, ISDB-T, or DTMB digital television, commonly on VHF or UHF

A3E

AM speech communication – used for aeronautical & amateur communications

F3E

FM speech communication – often used for marine radio and many other VHF communications

20K0 F3E

Wide FM, 20.0 kHz width, ±5 kHz deviation, still widely used for amateur radio, NOAA weather radio, marine, and aviation users and land mobile users below 50 MHz[2]

11K2 F3E

Narrow FM, 11.25 kHz bandwidth, ±2.5 kHz deviation – In the United States, all Part 90 Land Mobile Radio Service (LMRS) users operating above 50 MHz were required to upgrade to narrowband equipment by 1 January 2013.[3][4][5]

6K00 F3E

Even narrower FM, future roadmap for Land Mobile Radio Service (LMRS), already required on 700 MHz public safety band

J3E

SSB speech communication, used on HF bands by marine, aeronautical and amateur users

R3E

SSB with reduced carrier (AME) speech communication, primarily used on HF bands by the military (a.k.a. compatible sideband)

N0N

Continuous, unmodulated carrier, formerly common for radio direction finding (RDF) in marine and aeronautical navigation.

A1A

Signalling by keying the carrier directly, a.k.a. continuous wave (CW) or on–off keying, currently used in amateur radio. This is often but not necessarily Morse code.

A2A

Signalling by transmitting a modulated tone with a carrier, so that it can easily be heard using an ordinary AM receiver. It was formerly widely used for station identification of non-directional beacons, usually but not exclusively Morse code (an example of a modulated continuous wave, as opposed to A1A, above).

F1B

Frequency-shift keying (FSK) telegraphy, such as RTTY.[lower-alpha 1]

F1C

High frequency Radiofax

F2D

Data transmission by frequency modulation of a radio frequency carrier with an audio frequency FSK subcarrier. Often called AFSK/FM.

J2B

Phase-shift keying such as PSK31 (BPSK31)

P0N

Unmodulated Pulse-Doppler radar