Compendium

Everything an amateur radio operator should understand

286 short concept articles on antennas, radios, modes, electronics, propagation and operating. Not exam prep: the understanding behind the hobby. Use the contents on the left, or search.

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What is amateur radio?A licensed radio service for self-training, experimentation and public service, never for money.License classes and privilegesTechnician, General and Extra: what each adds and how upgrading works.Ways to get on the airA map of what operators actually do, from rag chewing to moonbounce.Electromagnetic wavesElectric and magnetic fields travelling together at the speed of light.How antennas workTurning current into radio waves and back again.Receiver basicsFrom antenna to speaker.GlossaryTerms from A to Z.

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The hobby

What amateur radio is, how licensing works, and the language of the air.

The amateur radio service · Licenses, call signs and rules · Speaking the language of the air16 articlesRadio fundamentals

Waves, the spectrum, how signals travel, and how information rides on them.

Waves and the spectrum · How signals travel · Signals and modulation29 articlesElectricity and electronics

The electrical engineering behind every radio: circuits, components, measurement and building.

Electrical basics · Reactance and AC theory · Components · Semiconductors · …57 articlesAntennas

Every common antenna, how each works, and the feed lines and hardware that connect them.

Antenna fundamentals · Wire antennas · Vertical and mobile antennas · Beam and directional antennas · …55 articlesTransceivers and station equipment

How radios work inside, the kinds you can buy, and everything around them in the shack.

How radios work · Types of radios · Radio controls and features · Station accessories and power30 articlesOperating modes

Phone, Morse code, digital and video: how each mode works and how to use it.

Voice (phone) · CW (Morse code) · Digital data modes · Digital voice and linked networks · …36 articlesThings to do with amateur radio

What operators actually do, from contests to satellites to hunting for hidden transmitters.

Everyday operating · Portable and outdoors · Space and the sky · Weak-signal and microwaves · …28 articlesEmergency and public service

How amateurs support their communities when normal communications fail.

Organizations and programs · Emergency practice11 articlesSafety, interference and compliance

Staying safe, and keeping your signal from causing (or suffering) trouble.

Safety · Interference and EMC14 articlesTools, tables and references

Software, online services and quick-look tables.

Software and online tools · Quick reference10 articles

Studying for an exam? The exam lessons teach the same ideas in the order the question pools ask them.