What is Ham Radio?

An amateur radio operator is an individual who typically uses equipment at an amateur radio station to engage in two-way personal communications with other similar individuals, on radio frequencies assigned to the amateur radio service by the Federal Communications Commission (FCC) in the United States and the International Telecommunication Union worldwide.

Amateur radio operators build and operate several types of amateur radio stations, including fixed ground stations, mobile stations, space stations and temporary field stations. A slang term often used for an amateur station's location is the "shack," named after the small enclosures added to the upper works of naval ships to hold early radio equipment and batteries.

American amateur radio operators are granted an amateur radio license by the FCC upon passing an examination on radio theory and operation. As a component of their license, amateur radio operators are assigned a call sign (such as KC9ANG) that they use to identify themselves during communications. There are about 3 million amateur radio operators worldwide, including more than 700,000 licensed operators in the United States alone.

Amateur radio operators are also known as radio amateurs or hams. The term "ham" as a pejorative nickname for amateur radio operators was first heard in 1909 by operators in commercial and professional radio communities. The word was subsequently embraced by the operators, and stuck. However, the term did not gain widespread usage in the United States until around 1920, after which it slowly spread to other English-speaking countries.

The term "amateur" in amateur radio is used in the same sense as an amateur athlete, as radio amateurs are prohibited by law from accepting monetary or material compensation of any kind for any activities they perform as radio operators. However, just as amateur athletes are among the top athletes in the world, ham radio operators have led the advancement of the science of radio communications for over a century. Today, we take for granted radio, television, satellite communications, cell phones, broadband, digital communications and many other innovations first explored and pioneered by ham radio hobbyists.

Today, radio amateurs are exploring voice and data communications in ever higher frequencies allocated for experimentation and exploration – extending all the way to 275 gigahertz (GHz) and even beyond, nearly to the spectrum of light. Amateur radio operators volunteer countless hours of community service in providing emergency communications during natural and man-made disasters, as well as public service communications in support of special events such as marathons, bike races, and public events.  Many are trained as severe weather spotters by the National Weather Service (NWS) and provide "ground truth," by mobile radio, to forecasters and emergency management agencies in support of public safety.


How to Talk to Someone Using Ham Radio:



A very short list of amateur radio terms:

AF (Audio Frequency)
AFC (Automatic Frequency Control) – automatically compensates for frequency drift.
AFSK (Audio Frequency Shift Keying)
AM (Amplitude Modulation)
AMSAT (AMateur SATellite) – amateur radio communications via orbiting satellites carrying amateur radio equipment installed before launching.
AMTOR (AMateur Teleprinting Over Radio) – a form of radio teletype.
ANT (ANTenna)
Antenna impedance – the impedance (or “resistance in an electric current to a flow of alternating current”) of an antenna at its resonance. Although an antenna’s impedance fluctuates with the frequency of operation, an antenna should be 50 Ω for most transceivers.
Antenna matching – to make sure that the antenna’s impedance at resonance is at optimum performance for your transmitter output circuit.
Antenna tuner – a device used to match an antenna to the output impedance of a transmitter.
APRS (Automatic Position Reporting System) – in conjunction with a GPS and TNC, provides position reporting.
ARES (Amateur Radio Emergency Service) – a public service organization of the American Radio Relay League.
ARRL (American Radio Relay League) – the national association for amateur radio in the United States.
ASCII (American National Standard Code for Information Interchange) – a seven-unit digital code for the transmission of teleprinter data.
ATV (Amateur Television) – sending television signals over amateur radio frequencies.
Autopatch – used for telephone connection to amateur radio equipment.
Average power – power, as measured on a standard power meter.

Backscatter – a form of ionosphere propagation of radio transmissions.
Band – a range of frequencies.
Bandwidth – frequency needed for a particular type of radio transmission.
BFO (Beat Frequency Oscillator)
BNC (Bayonet Neill-Concelman) – a type of antenna connector.
BPF (BandPass Filter) – allows only certain ranges of frequencies to be received or transmitted.

Call sign – a unique sequence of letters and numbers used to identify amateur radio operators and issued by the FCC.
Carrier wave – an unmodulated transmitted signal.
CBR (Cross Band Repeater) – a repeater which receives incoming signals and retransmits them in different bands; e.g., receives 144 megahertz (MHz) bands and retransmits 430-440 MHz bands.
Club station – in the United States, special call signs might be made available for clubs, and are frequently used at a club station established for use by the club's members.
CPU (Central Processing Unit)
CQ – radio communications term used to call others.
CW – carrier wave (Morse Code communications).

Data communications – transfer of data between two or more locations.
dBd – unit of RF power as compared to a dipole antenna.
dBi – unit of RF power as compared to an isotropic antenna.
dBm – decibel measure; 1 mW with a load impedance of 600 Ω (0 dBm=1 mW).
DC (Direct Current)
DC ground – a connection point directly to a chassis or battery ground to prevent the buildup of hazardous DC voltages.
Deviation – measurement for FM signals for the maximum carrier frequency changes on either side of the carrier frequency.
Distress call – signals a life-threatening situation. Most commonly referred to as an SOS or MAYDAY call.
Distress frequency – a frequency or channel specific for use in distress calling. Radiotelephone
distress frequencies are 2.182 MHz and 156.8 MHz. Survival craft use 243 MHz. Maritime distress frequencies are the same, while general aviation frequencies are 121.5 MHz.
Downlink (↔Uplink) – the frequency that a repeater or satellite transmits on to a user.
DSP (Digital Signal Processor) – used to improve the signal-to-noise ratio, for clearer and more legible communication. Relatively new to the ham radio.
DTCS (Digital Tone Coded Squelch) – a selective call system.
DTMF (Dual Tone Multi-Frequency (or touch-tone)) – used to transmit and/or receive numeric information, such as phone numbers or remote radio control commands.
Dummy load – a nonradiating 50-ohm load connected to the transmitter, instead of to an antenna, for testing purposes.
Duplex – an operation mode in which the transmit and receive frequencies are different.
Dx’pedition – a trip to a foreign country to set up and operate amateur stations in exotic locations.

EME (Earth-Moon-Earth) – radio signals bounced off the moon and returned to Earth.
EMI (Electro-Magnetic Interference) – often called RFI (Radio-Frequency Interference).
Emission – transmission of a signal.

Fading – signal reduction due to atmospherics.
FCC (Federal Communications Commission)
Filter – a circuit designed to pass only the desired frequency(s).
FM (Frequency Modulation)
FSK (Frequency Shift Keying)
FSTV (Fast Scan TV) – graphics (and audio) communication using TV broadcast signals.
Full duplex – an operation mode which transmits and receives on different frequencies at the same time, as in a normal telephone conversation.
Ground Plane – a type of omnidirectional antenna
Ground Wave – electrical wave directly travelling from transmitter.
Grounding – electrical connection to the earth.

Harmonic – multiple of a fundamental frequency.
HF (High Frequency) – 3-30 MHz-range signals. Commonly known as “short wave.”
HPF (High Pass Filter)
Hz (Hertz) – one cycle of an electromagnetic wave. A “KHz” is 1,000 cycles per second. A “MHz” is 1 million cycles per second.
IC (Integrated Circuit)
IF (Intermediate Frequency) – internally converted frequency for amplification and other signal
IF shift – a function that electronically shifts IF frequency from a center frequency.
IMD (Inter-Modulation Distortion) – distortion within RF circuits made with upper and lower adjacent channel signals.

LF (Low Frequency) – 30-300 KHz-range signals.
LPF (Low Pass Filter)
LSB (Lower Side Band)

MARS (Military Affiliate Radio Service)
MF (Medium Frequency) – 300 kHz to 3 MHz-range signals, as in AM radio stations.
MIC (MICrophone)
Modulation – method of adding information to a radio frequency carrier.
Morse Code – a very efficient method of communication (see CW) using the International Morse Code. Many hams prefer this method of radio communication over all others.

NB (Noise Blanker) – a function reducing pulse-type noises.
NBFM (Narrow Band FM)
Notch filter – sharp and narrow rejection filter for elimination of interfering signals.
NR (Noise Reduction) – this DSP feature reduces unwanted signal noise.

Offset frequency – frequency difference between transmit and receive frequencies.
OSC (OSCillator) – generates radio frequency signals within transmitters.

PA (Power Amplifier)
PEP (Peak Envelope Power) – RF power at maximum amplitude.
PLL (Phase Locked Loop) – a circuit to synthesize different frequencies for operation.
PTT (Push To Talk)

Reflected power – nonradiated power dissipated as heat when the transmitter is mismatched to the antenna or load.
Repeaters – radio systems which receive incoming signals and retransmit them for an extended communication area. Normally put on geographically high locations for VHF/UHF hand portables.
RF (Radio Frequency)
RF ground – connection of amateur equipment to Earth ground to eliminate hazards from RF exposure and reduce RFI.
RFI (Radio Frequency Interference)
RTTY (Radio TeleTYpe)
RX (Receive)

S/N (Signal to Noise ratio)
SAR (Search And Rescue)
Scan – continually sweeping frequencies looking for signals.
Sensitivity – indicates how weak a signal the receiver will pick up.
Silent Key term for a ham radio operator who has passed away.
SKYWARN – trained volunteer storm spotters for the National Weather Service.
SMA (Sub-Miniature coaxial cable connector) – type of antenna connector, used in VHF/UHF portables.
SP (SPeaker)
Split – mode in which the transmit and receive frequencies are different.
SQL (SQueLch) – a function that mutes audio output unless a strong signal is received.
SSB (Single Side Band)
SSTV (Slow Scan TV) – graphics and image/voice transmission using narrow bandwidth.
SWL (Short Wave Listener) – listening to international short wave bands for enjoyment.
SWR (Standing Wave Ratio) – measurement of forward vs. reflected power output during transmit.

TNC (Terminal Node Controller) – for digital data communication. Also a type of antenna connector.
TX (Transmit)

UHF (Ultra High Frequency) – 300 MHz to 3 GHz-range signals. This range includes “microwave” frequencies with antennas only a fraction of an inch long.
Uplink (↔Downlink) – frequencies used to communicate with the repeater or satellite.
USB (Upper Side Band)
UTC (Universal Time Coordinated) – an astronomical time based on the Greenwich meridian (zero degrees longitude, passing through Greenwich, England).

VFO (Variable Frequency Oscillator) – an operation mode in which the operator can change frequencies freely.
VHF (Very High Frequency) – 30-300 MHz-range signals, as in TV and FM radio stations.
VLF (Very Low Frequency) – under 30-KHz-range signals. Characterized by very long wavelengths.  Long used for military communications with submerged submarines.
VOX (Voice Operated transmission)