Ham Radio Technician key terms

A radio communication service, authorized under Part 97, for licensed operators interested in radio technique solely with a personal aim and without financial interest.

The section of Title 47 of the Code of Federal Regulations that contains the rules governing the Amateur Radio Service in the United States.

The Federal Communications Commission, the U.S. government agency that regulates interstate and international radio communications and issues amateur licenses and call signs.

A license granted by the FCC in one of three classes - Technician, General, or Amateur Extra - that authorizes the holder to transmit on specified amateur frequencies.

The entry-level amateur license class, granting full privileges on bands above 30 MHz plus limited HF privileges, including certain portions of the 80, 40, 15, and 10 meter bands.

A unique identifier assigned by the FCC to an amateur station, used to identify the station at the beginning and end of each transmission and every ten minutes during a contact.

The required announcement of a station's assigned call sign at the start and end of a communication and at least every ten minutes during it, using the station's authorized identifier.

A licensed amateur designated by the station licensee to be responsible for the proper operation of the station at all times, including compliance with FCC rules.

The person who holds the FCC license for an amateur station and is ultimately responsible for its operation, whether or not present at the control point.

The location where the control operator of an amateur station is located and from which the station's transmissions are managed and can be terminated.

The specific bands and sub-band segments an amateur may use, determined by license class and defined by emission type and maximum power in the FCC rules.

A voluntary, published arrangement of frequencies within an amateur band that recommends where each operating mode, such as CW, phone, or digital, should be used.

A frequency, often at the low or high end of a band segment, where operators listen for and initiate contacts before moving to another frequency to continue.

A general invitation transmitted to any station that may be listening, indicating the caller wishes to make contact with an unknown operator.

A two-way radio communication between amateur stations, which may be brief for contest or signal-report purposes or extended for conversation.

A message passed by an amateur station on behalf of a person other than the control operator, permitted only when the rules allow and the message does not involve business or political purposes.

A three-part signal report giving readability, signal strength, and tone, used by operators to describe received signal quality during a contact.

A short standardized description of how well a station's signal is being received, commonly expressed as an RST value or a plain readability and strength assessment.

An automatically controlled station that receives a signal on one frequency and simultaneously retransmits it on another, extending the range of handheld and mobile stations.

The fixed frequency difference between a repeater's input and output frequencies, typically 600 kHz on 2 meters and 5 MHz on 70 centimeters.

Continuous Tone-Coded Squelch System, a subaudible tone transmitted with a signal so a repeater or receiver opens its squelch only for signals carrying the matching tone.

A receiver circuit that mutes audio output unless the received signal exceeds a set threshold, suppressing background noise when no signal is present.

A single unit combining a transmitter and receiver that share circuitry and an antenna connection, allowing an operator to transmit and receive from one device.

The equipment that generates a radio-frequency signal, modulates it with information, and amplifies it for delivery to the antenna for radiation.

The process of varying a radio-frequency carrier, in amplitude, frequency, or phase, so that it carries voice, data, or other information to a receiver.

Frequency modulation, a mode in which the carrier's frequency shifts in step with the information signal, offering good noise immunity and the standard mode for VHF/UHF voice repeaters.

Single sideband, an amplitude-modulation variant that transmits only one sideband and suppresses the carrier, using less bandwidth and power than full AM.

Continuous wave, the on-off keying of an unmodulated carrier to send Morse code, the narrowest and most power-efficient of the common amateur modes.

The range of frequencies occupied by a transmitted signal, measured in hertz, which determines how much of a band the emission consumes.

The number of complete cycles of an alternating signal per second, expressed in hertz and determining which band and wavelength an emission occupies.

The physical distance a radio wave travels during one complete cycle, equal to the speed of light divided by the frequency, and used to name amateur bands.

A contiguous range of frequencies designated for a service, such as the 2 meter or 20 meter amateur band, each with its own privileges and propagation behavior.

The relationship stating that voltage equals current multiplied by resistance, used to calculate any one of the three quantities when the other two are known.

The rate at which electrical energy is used or radiated, equal to voltage times current and measured in watts; transmitter output power is regulated by band and license class.

The power a station actually radiates in a given direction, calculated from transmitter output, feed line loss, and antenna gain, and used for regulatory power limits.

A conductor or system of conductors that converts radio-frequency current from a transmitter into radiated electromagnetic waves, and incoming waves back into current.

The measure, usually in decibels, of how much more strongly an antenna radiates or receives in a favored direction compared with a reference antenna.

The transmission line, commonly coaxial cable, that carries radio-frequency energy between the transceiver and the antenna while minimizing loss and unwanted radiation.

A ratio describing how well an antenna system matches the transmitter's impedance; a value near 1:1 indicates a good match and minimal reflected power.

The total opposition a circuit presents to alternating current, combining resistance and reactance, measured in ohms and typically 50 ohms in amateur equipment.