Technician License Study Guide - Glossary Flashcards
alternating current. Alternating current is the name for current that reverses direction on a regular basis. The power outlets in your home provide alternating current.
AC
Automatic Packet Reporting System. Digital communications system used by amateur radio operators. While it is normally used for tracking the location of mobile stations, it can be used for other purposes as well. For more information, go to http://www.aprs.org.
APRS
Amateur Radio Emergency Service consists of licensed amateurs who have voluntarily registered their qualifications and equipment with their local ARES leadership for communications duty in the public service when disaster strikes. For more information,
go to http://www.arrl.org/ares.
ARES
amplitude modulation. The type of modulation that varies the amplitude of a radio signal in accordance with the amplitude of a modulating signal. For more information, go to http://www.pa2old.nl/files/am_fundamentals.pdf.
AM
plan showing how frequencies within a particular amateur radio band are assigned to
different modes so that operators may avoid interfering with one another.
band plan
directional antenna.
beam antenna
Continuous Tone Coded Squelch System. A system that uses sub-audible tones, transmitted along with the audio portion of a transmission to control whether or not a repeater will re-transmit a signal. It is known by a number of different trade names, including Private Line® (PL) by Motorola. In
practice, it’s used to prevent nearby transmitters from inadvertently turning on repeaters.
CTCSS
continuous wave. This is the operating mode amateur radio operators use when sending Morse
Code.
CW
direct current. Direct current is the name for current that never reverses direction.
Digital Mobile Radio: radio standard for time-division multiplexing two digital voice signals on a 12.5
KHz repeater channel.
DC
Digital Mobile Radio
DMR
dual-tone, multi-frequency. DTMF is a type of signaling used to send data over voice channels. Its most common use in amateur radio is to allow users of handheld transceivers to send commands to repeater systems. It is called DTMF because every time a user presses a keypad button a unique tone
consisting of two frequencies is transmitted. For more information, see
http://www.genave.com/dtmf.htm.
DTMF
system that links amateur radio stations and computing devices using Voice over IP
(VOIP). electromotive force (EMF): force that propels electric charge through a conductor or circuit; expressed 121in volts (V).
EchoLink
Federal Communications Commission. This is the government body which sets the rules for
amateur radio in the U.S.
FCC
wire or cable that carries signals from a transmitter to an antenna or from an antenna to a
receiver.
feed line
frequency modulation. The type of modulation normally used when operating on VHF and UHF
repeaters.
FM
data transmission protocols designed for very weak signal communication.
FT8
high frequency. The range of frequencies between 3 MHz and 30 MHz.
HF
handy-talky or handheld transceiver. “Handy Talky” is a Motorola trademark.
HT
International Telecommunications Union. This is the international body which governs amateur
radio worldwide.
ITU
lower sideband. See SSB.
LSB
multi-frequency shift keying. A type of modulation used to send digital information over a
radio channel.
MFSK
Private Line. See CTCSS.
PL
male connector often used to connect feedlines to a radio.
polarization: orientation of the electric field a radio wave.
PL-259
phase shift keying. A method for sending digital information over a radio channel. A popular amateur radio “digital mode” is PSK31, which uses PSK modulation and occupies only 31 Hz of
bandwidth.
PSK
push-to-talk
PTT
Radio Amateur Civil Emergency Service. RACES is an amateur radio emergency
communications service created by the Federal Emergency Management Agency (FEMA) and the FCC. RACES volunteers serve their respective jurisdictions pursuant to guidelines and mandates established
by local emergency management officials. See http://www.usraces.org/ for more information.
RACES
receiver incremental tuning. A control which allows a user to set the receive frequency of a
transceiver either slightly higher or slightly lower than the transmit frequency.
RIT
radio frequency
RF
single sideband. When a carrier is amplitude modulated, both upper and lower sidebands are produced. This results in a signal that is 6 kHz wide. Since both sidebands carry the same information, and the carrier carries no information, someone figured out that if they could filter out the carrier and one of the sidebands, and put all the power into a single sideband, the efficiency of voice SSB:
SSB
standing-wave ratio. The SWR of an antenna system is a measure of how closely the impedances of the antenna and feedline match the output impedance of the transmitter.
SWR
virtual channel that connects amateur radio operators through a repeater or over the internet.
talk group
very high frequency. The range of frequencies between 30 MHz and 300 MHz.
VHF
Universal Licensing System. The FCC’s Universal Licensing system contains information on all FCC licensees, including amateur radio operators. For more information, go to http://www.fcc.gov/uls.
ULS
ultra high frequency. The range of frequencies between 300 MHz and 3000 MHz. 41
UHF
upper sideband. See SSB.
USB
variable frequency oscillator. VFOs are used to control the receiving and transmitting frequencies of amateur radio equipment.
VFO
amateur radio software developed by Joe Taylor, K1JT, that supports weak-signal and low-power digital communication modes, such as
- JT65, JT4, JT9, and QRA64 (EME);
- FSK441and JTMS (meteor scatter);
- JT6M and ISCAT (ionospheric scatter), and
- FT8 and FT4.
WSJT, WSJT-X
