Glossary

Every acronym and technical word from the lessons, explained for someone who has never used a radio. In the lessons, click an underlined word to see its explanation.

2 m and 70 cm: Radio amateur bands named after the length of their radio waves: 2 m is 144–146 MHz, 70 cm is 430–440 MHz. Most local amateur talk in FM happens here. Lesson 11
Alkaline batteries: Ordinary single-use batteries. They work in the IC-R5, but must never be charged. Lesson 2
AM (amplitude modulation): The sound changes the strength of the radio wave. Used for medium-wave and shortwave broadcasting and for aviation. Lesson 6
Analogue: The classic way of sending sound by radio, where the wave follows the sound directly (AM and FM). The opposite of digital, which sends sound as numbers. Lesson 7
Antenna: The part that catches radio waves from the air. A better or higher antenna usually makes more difference than anything else. Lesson 12
ARISS: Amateur Radio on the International Space Station: the programme that lets school pupils talk with astronauts by radio. Lesson 11
Attenuator (ATT): A switch that makes all incoming signals weaker. Useful next to a very strong transmitter that would otherwise overload the receiver and make stations appear where they don't belong. Lesson 12
Band: A range of frequencies used for one kind of radio, like the FM broadcast band from 87.5 to 108 MHz. The BAND key jumps from one band to the next. Lesson 4
Bar antenna: A small antenna inside the radio: a coil of wire on a ferrite rod. It works well for medium wave and is directional, so turning the radio changes the reception. Lesson 12
BIPT: The Belgian Institute for Postal Services and Telecommunications, Belgium's telecom regulator. It decides how radio may be used in Belgium. Lesson 7
BNC connector: A larger antenna connector that locks with a push and a twist. It doesn't fit the IC-R5 directly; you need an AD-92SMA adapter. Lesson 12
Broadcasting: Radio meant for everyone, such as music and news stations. Always free to listen to. Lesson 7
Calling channel: An agreed frequency where people call to start a conversation, then move to another frequency to talk. A radio meeting point. Lesson 11
CB (citizens band): 40 licence-free channels around 27 MHz, used by truck drivers and hobbyists to chat. Free to listen to. Lesson 10
CTCSS, privacy codes: A tone too low to hear, sent along with a transmission, so only radios set to the same tone open their speaker. Despite the name, it doesn't make anything private: other radios can still hear everything. Lesson 10
DAB+ (digital radio): Digital radio broadcasting. The IC-R5 can't decode it; it only hears a rough buzz. Lesson 7
Dial-select step (D SEL): The size of the big jumps when you turn the dial while holding FUNC: 100 kHz, 1 MHz (the default) or 10 MHz. Lesson 13
DMR (digital mobile radio): A digital radio system used by companies and some radio amateurs. The IC-R5 can't decode it. Lesson 7
Doppler shift: The change in frequency when a transmitter moves towards or away from you, like the pitch of a passing ambulance siren. The fast-moving ISS shifts by a few kHz. Lesson 11
Downlink: The frequency a satellite or space station uses to transmit down to Earth. Lesson 11
Duplex, offset: Using two different frequencies, one to send and one to receive, as repeaters do. The difference between them is the offset: 600 kHz on 2 m. Lesson 11
Encrypted: Scrambled with a secret key, so only authorised radios can understand it. Lesson 7
FM (frequency modulation): The sound makes the frequency wobble slightly. On the IC-R5, "FM" means narrow FM: walkie-talkies, radio amateurs and CB. "FM radio" in everyday speech means the broadcast stations, which use WFM. Lesson 6
Frequency: Where on the dial a signal is. Every transmitter sends on its own frequency, a bit like a house number; tune the radio to that number and you hear it. Frequencies are counted in hertz: MHz or kHz. Lesson 4
HF, shortwave: Frequencies from about 3 to 30 MHz. Shortwave signals bounce off the upper atmosphere and can travel thousands of kilometres, especially in the evening. Lesson 12
ISS (International Space Station): The crewed space station circling the Earth about 400 km up, once every 90 minutes. It has an amateur radio station on board. Lesson 11
kHz (kilohertz): One thousand vibrations per second, a thousandth of a MHz. Small distances on the dial, like the 12.5 kHz between two channels, are given in kHz. Lesson 4
LCD (liquid crystal display): The radio's small screen, showing the frequency, the mode and status icons. Lesson 1
Medium wave: The AM broadcast band, 531 to 1602 kHz in Europe. Belgium's own stations have gone, but at night you can hear stations from far away. Lesson 12
Memory channel: A saved frequency, with its mode, that you can call back instantly, like a preset button on a car radio. The IC-R5 has 1000 of them. Lesson 8
MHz (megahertz): A unit of frequency: one million vibrations per second. Radio frequencies are usually given in MHz, like 100.6 MHz for a radio station. Lesson 4
Modulation: How sound is put onto a radio wave so it can travel. AM and FM are the two kinds the IC-R5 understands. Lesson 6
Monitor: Opening the squelch for a moment (hold SQL) to hear weak signals or check whether a frequency is really quiet. Lesson 3
NiCd batteries: Nickel-cadmium: an older kind of rechargeable battery that the IC-R5 can also charge. Lesson 2
NiMH batteries: Nickel-metal hydride: the common rechargeable AA battery. The best choice for the IC-R5, which can charge them itself. Lesson 2
PMR446: Licence-free walkie-talkies on 16 channels around 446 MHz, the kind you buy in a toy or outdoor shop. PMR stands for private mobile radio. Free to listen to. Lesson 10
Priority watch: Checks one saved channel every 5 seconds while you listen somewhere else, so you don't miss it. Lesson 13
Radio amateur: A hobbyist with a licence to transmit, who talks with others nearby and around the world, often on home-built gear. Everyone may listen to them. Lesson 11
Receive mode: The way the sound is carried on the radio wave: AM, FM or WFM. The radio must use the same mode as the transmitter, or it sounds distorted or nearly silent. Lesson 6
Receiver: A device that picks up radio signals and turns them into sound. The IC-R5 is only a receiver: it cannot send anything, so you can't disturb anyone with it.
Repeater: An automatic station on a hill or tower that picks up a signal and sends it out again on another frequency, so small handheld radios reach much further. Lesson 11
Scanner, scanning: Scanning means letting the radio step through frequencies or saved channels on its own, stopping whenever it hears something. A receiver that can do this is often called a scanner. Lesson 9
Set mode: The IC-R5's settings menu. Hold TS for a second to open it. Lesson 13
Signal bars (S-meter): The bars at the bottom of the display show how strong the signal you're receiving is. More bars, stronger signal. Lesson 5
Skip: A mark on a memory channel that makes the scan jump over it. Lesson 9
SMA connector: A small screw-on connector for antennas (SubMiniature version A). The IC-R5's antenna screws onto the SMA socket on top, and any other antenna with an SMA plug fits too. Lesson 1
Squelch: A gate that keeps the speaker quiet while nobody is transmitting. Without it you would hear constant hiss; it opens by itself when a signal comes in. Lesson 3
SSB (single sideband): A narrow kind of AM used by radio amateurs and on shortwave. The IC-R5 can't receive it properly: it sounds like a garbled duck voice.
SSTV (slow-scan television): Pictures sent as sound over the radio. The ISS sometimes sends SSTV images; a free phone app can turn the sound back into the picture. Lesson 11
TETRA, ASTRID: TETRA is a digital radio system for emergency services. ASTRID is Belgium's TETRA network for police, fire brigades and ambulances. It is encrypted and listening to it is not allowed. Lesson 7
Transmitter: The device that sends out a radio signal, from a big broadcast tower to a small walkie-talkie. In Dutch the same word, "zender", also means a radio station.
Tuning step: How far the frequency moves with one click of the dial, for example 12.5 kHz. Set it to the distance between channels, so every click lands exactly on the next one. Lesson 4
UBA: Belgium's national radio amateur association (Koninklijke Unie van de Belgische Zendamateurs). It keeps the official list of Belgian repeaters. Lesson 11
UHF (ultra high frequency): Radio waves from 300 to 3000 MHz. PMR446 walkie-talkies, 70 cm radio amateurs and digital TV are on UHF.
VFO (variable frequency oscillator): The normal mode, where you tune freely with the dial. The other mode is memory mode, where the dial steps through your saved channels. Lesson 8
VHF (very high frequency): Radio waves from 30 to 300 MHz. FM radio stations, 2 m radio amateurs, aviation and marine radio are all on VHF.
WFM (wide FM): The wide version of FM used by FM radio stations between 87.5 and 108 MHz. It sounds better, but each station takes up more room on the dial. Lesson 6