Contents
Amateur Radio Fundamentals
How Amateur Radio Works
Types of Amateur Radio
How to Get an Amateur Radio License
Amateur Radio Equipment
How to Set Up a Radio Shack
How to Get on the Air
Amateur Radio Clubs and Activities
Amateur Radio Codes, Abbreviations, and Lingo
FCC Rules and Regulations
Morse Code
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How Amateur Radio Works
To make the most of amateur radio’s many uses, you first need a firm grasp of the technology behind the hobby.
Radio Waves
All electromagnetic radiation—which includes gamma rays, X-rays, ultraviolet light, visible light, infrared light, and radio waves—moves in the form of waves, which are defined by their wavelength and frequency.
- Wavelength: The distance between two successive crests of a wave. A complete wave cycle consists of one wavelength.
- Frequency: The number of complete wave cycles generated in one second, expressed in hertz (Hz). A 20-Hz frequency has 20 cycles per second.
Together, all of the different types of radiation make up the electromagnetic spectrum, with radio waves having the longest wavelengths and lowest frequencies.
The Radio Frequency (RF) Spectrum
The radio frequency (RF) spectrum, the portion of the electromagnetic spectrum suitable for radio communications, ranges from about 10,000–300 billion Hz. The RF is divided into five main bands, or frequency ranges, each of which has a unique set of characteristics, uses, and regulations. Each of these main bands is further split into various sub-bands, which are also referred to as bands.
- Medium frequency (MF): 0.300–MHz (1 megahertz, or MHz, equals 1 million hertz)
- High frequency (HF): 3–30 MHz
- Very high frequency (VHF): 30–300 MHz
- Ultra high frequency (UHF): 300 MHz–1 GHz (1 gigahertz, or GHz, equals 1 billion hertz)
- Microwave: Above 1 GHz
The most popular types of amateur radio activities use HF and VHF bands (for more on popular types of amateur radio, see Types of Amateur Radio).
Band Plans
Since all radio communication is limited to a finite number of bands, amateur radio operators can’t all use the same bands at once. One role of the Federal Communications Commission (FCC) is to monitor all commercial and amateur radio traffic In order to limit interference among the
millions of users vying for space on the bands described above. The FCC creates band plans, rules that specify the types of radio communication that are permitted on each main band and its various sub-bands. For instance, amateur AM radio communication must use certain sub-bands within the HF band (3–30MHz). For a complete list of sub-bands and the type of communication each should carry, see www.arrl.org/FandES/field/regulations/bandplan.html.
How to Transmit and Receive Radio Waves
Amateur radio operators use transceivers to transmit and receive radio waves. Transceivers can transmit and receive radio waves encoded with sound, data, still images, or video. Radio transceivers usually feature many dials and switches that allow the operator to control the type of radio waves to transmit, the band on which to operate, whether to call (connect with) another operator, and so on. The two main dials are the oscillator and the mode selector:
- Oscillator: Controls the frequency of the waves that the transmitter generates and transmits
- Mode selector: Modifies the main signal sent from the transmitter in order to encode it with data, such as text, sound, or images
How Transceivers Work
Amateur radio transceivers set electrons into motion, which in turn generate fields of radio waves that radiate from the antenna. These transceivers use various frequencies to send signals from one transceiver to another. Some frequencies propagate as ground waves, which travel close to the earth’s surface. Others propagate as sky waves, which bounce off the ionosphere, the layer of earth’s atmosphere that contains high levels of ions and free electrons.
Repeaters
An amateur radio repeater is an electronic device that receives weak amateur radio signals, amplifies them, and retransmits them in order to extend their range. Repeaters can be maintained by individual hobbyists or by amateur radio clubs or other enthusiast groups. The ARRL publishes an annual nationwide directory of repeaters. You can buy it online at www.arrl.org/catalog/?item=9590.
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