N
National electrical code : a set of
guidelines governing electrical safety, including antennas.
NB : (Noise Blanker) a function
reducing pulse-type noises.
NBFM : (Narrow Band FM)
Near field of an antenna : the
region of the electromagnetic field immediately surrounding an antenna where the
reactive field dominates and where the field strength as a function of angle
(antenna pattern) depends upon the distance from the antenna. It is a region in
which the electric and magnetic fields do not have a substantial plane-wave
character, but vary considerably from point-to-point.
Negative feedback : the process in
which a portion of the amplifier output is returned to the input, 180 degrees
out of phase with the input signal.
Negative offset : the repeater input frequency is lower
than the output frequency.
Net : a group of amateurs who meet
at regular times on a specific frequency to share common interests and to
prepare themselves for organization during emergency communications.
Network : a term used to describe
several packet stations linked together to transmit data over long distances.
Neutralization : feeding part of
the output signal from an amplifier back to the input so it arrives out of phase
with the input. This negative feedback neutralizes the effect of positive
feedback caused by coupling between the input and output circuits in the
amplifier.
Ni-Cd: a nickel-cadmium battery that may be
recharged many times; often used to power portable transceivers.
Pronounced "NYE-cad."
Ni-MH : a nickel-metal hydride battery
that may be recharged many times; often used to power portable transceivers.
Noise bridge : a test instrument used to
determine the impedance of an antenna system.
Nonionizing radiation : electromagnetic radiation
that does not have sufficient energy to knock electrons free from their atoms.
Radio frequency (RF) radiation is nonionizing.
Notch filter: sharp and narrow rejection filter
for elimination of interfering signals.
NPN transistor : a transistor that has a layer of
P-type semiconductor material sandwiched between layers of N-type semiconductor
material.
NR : (Noise Reduction) DSP feature reduces
unwanted signal noise.
TOP
O
Odd split : unconventional frequency separation between input and
output frequencies.
Offset : the 300 to 1,000 hertz difference in CW
transmitting and receiving frequencies in a transceiver. For a repeater, offset
refers to the difference between its transmitting and receiving frequencies. See
also Separation.
Offset frequency : frequency difference between
transmit and receive.
Ohm : the basic unit of electrical resistance,
used to describe the amount of opposition to current.
Ohm's law : a basic law of electronics. Ohm's law
gives a relationship between voltage (E), current (I), and resistance (R). The
voltage applied to a circuit is equal to the current through the circuit times
the resistance of the circuit (E=IR).
One-way communications : transmissions that are
not intended to be answered. The FCC strictly limits the types of one-way
communications allowed on the amateur bands.
Open circuit : an electrical circuit that does
not have a complete path, so current can't flow through the circuit.
Open repeater : a repeater whose access is not limited.
Operator/primary station license : an amateur
license actually includes two licenses in one. The operator license is that
portion of an Amateur Radio license that gives permission to operate an amateur
station. The primary station license is that portion of an Amateur Radio license
that authorizes an amateur station at a specific location. The station license
also lists the call sign of that station.
OSC : (OSCillator)
Oscilloscope : an electronic test instrument
used to observe wave forms and voltages on a cathode-ray tube.
Output frequency : the frequency of the repeater's transmitter (and
your receiver).
Over : the word used to indicate the end of a voice transmission.
TOP
P
PA : (Power Amplifier)
Packet radio : a system of digital communication
where by information is broken into short bursts. The bursts
("packets") also contain addressing and error detection
information.
Parallel circuit : an electrical circuit in which
the electrons follow more than one path in going from the negative supply
terminal to the positive terminal.
Parallel-conductor feed line : feed line
constructed of two wires held at a constant distance apart; either incased in
plastic or constructed with insulating spacers placed at intervals along the
line.
Parasitic beam antenna : another name for the beam
antenna.
Parasitic element : part of a directive antenna
that derives energy from mutual coupling with the driven element. Parasitic
elements are not connected directly to the feed line.
Parawatch : (same as Dualwatch)
PBT : (PassBand Tuning) a function that
electronically reduces interference by narrowing IF bandwidth.
Peak envelope power (PEP) : the average power of
a signal at its largest amplitude peak.
Peak-inverse-voltage (PIV) : the maximum
voltage a diode can withstand when it is reverse biased (not conducting).
PLL : (Phase Locked Loop) circuit to synthesis
the difference frequencies a radio will operate on.
Pecuniary : payment of any type, whether money or
other goods. Amateurs may not operate their stations in return for any type of
payment.
Phase : the time interval between one event and
another in a regularly recurring cycle.
Phase modulation : varying the phase of an RF
carrier in response to the instantaneous changes in an audio signal.
Phone : another name for voice communications.
Phone emission : the FCC name for voice or other
sound transmissions.
Phonetic alphabet : standard words used on voice
modes to make it easier to understand letters of the alphabet, such as those in
call signs. The call sign KCØDMH stated phonetically is Kilo Charlie Zero Delta
Mike Hotel.
Photovoltaic cell : a wafer of semiconductor
material that produces electricity when light shines on it. Sometimes called a
solar cell, each cell produces about one-half volt when fully illuminated. Cells
are connected in series to increase the voltage. The size or surface area of the
cell determines the maximum current that the cell can supply. An array of cells
forms a solar panel that can be used to charge a led-acid storage battery.
Photovoltaic conversion : the process by which
a semiconductor PN junction changes sunlight directly into energy.
Picket fencing: if a repeater user's signal
isn't strong enough to maintain solid access to the machine's
input (such as when operating from a vehicle passing beneath
underpasses or through hilly terrain), the signal would be hard
to copy because of a pronounced, rapid fluttery or choppy
characteristic. It sounds as if the transmitting station is
passing behind a picket fence that alternately blocks and passes
its signals. Picket fencing usually ceases when the transmitting
station moves closer to the repeater or into a clearer location.
Pico : the metric prefix for 10^-12, or
divide by 1,000,000,000,000.
PL : Private Line (trademark of Motorola Inc) see
CTCSS.
PNP transistor : a transistor that has a layer of
N-type semiconductor sandwiched between layers of P-type semiconductor material.
Pocket beep : beeping function when a specific
signal is received.
Polarization: the electrical-field characteristic
of a radio wave. An antenna that is parallel to the surface of the earth, such
as a dipole, produces horizontally polarized waves. One that is perpendicular to
the earth's surface, such as a quarter-wave vertical, produces vertically
polarized waves. An antenna that has both horizontal and vertical polarization
is said to be circularly polarized.
Portable device : a radio transmitting device
designed to have a transmitting antenna that is generally within 20 centimeters
of a human body. See also hand-held.
Positive offset : the repeater input frequency is higher than the
output frequency.
Potentiometer : another name for a variable
resistor. The value of a potentiometer can be changed over a range of values
without removing it from a circuit.
Power : the rate of energy consumption. We
calculate power in an electrical circuit by multiplying the voltage applied to
the circuit times the current through the circuit (P=IE).
Power density : a measure of the power flow
through a unit area normal (perpendicular) to the direction of propagation. It
is usually expressed in watts per square meter (W/m²).
Power supply : a circuit that provides a direct
current output at some desired voltage from an ac input voltage.
Primary winding : the coil in a transformer
that is connected to the energy source.
Priority traffic : emergency related messages,
but not as important as Emergency traffic.
Priority watch : reception mode, which by a
selected frequency is always periodically, checked when VFO is set to a
different frequency.
Procedural signal (prosign) : one or two letters
sent as a single character. Amateurs use prosigns in CW contacts as a short way
to indicate the operator's intention. Some examples are K for "go
ahead" or AR for "end of message". Double letters are sent as one
character.
Product detector : a device that allows a
receiver to process CW and SSB signals.
Propagation : the study of how radio waves
travel.
PTT (Push To Talk) : the use of the microphone button or control line
to key the transmitter on.
Pulsating dc : the output from a rectifier
before it is filtered. The polarity of a pulsating dc source does not change,
but the amplitude of the voltage changes with time.
PWR : (PoWeR)
TOP
Q
Q signals : three-letter symbols
beginning with Q. Used on CW to save time and to improve communication. Some
examples are QRS (send slower), QTH (location), QSO (ham conversation), and QSL
(acknowledgement of receipt).
QRL? : ham radio Q signal meaning
"is the frequency in use?"
QSL card : a postcard that serves as
confirmation of communication between two hams.
QSO : a conversation between two
radio amateurs.
Quarter-wavelength vertical antenna : an
antenna constructed of a quarter-wavelength long radiating element placed
perpendicular to the earth.
TOP
R
Radio Amateur Civil Emergency Service (RACES) : a
part of the Amateur Service that provides radio communications for civil
preparedness organizations during local, regional, or national civil
emergencies.
Radio frequency interference (RFI) : disturbance
to electronic equipment caused by radio frequency signals.
Radioteletype (RTTY) : radio signals sent from
one teleprinter machine to another machine. Anything that one operator types on
a teleprinter will be printed on the other machine. Also known as narrow-band
direct-printing telegraphy.
Random-length wire antenna : a multiband
antenna consisting of any convenient length of wire, connected directly to a
transmitter or impedance-matching network without the use of feed line.
Reactance : the opposition to current that a
capacitor or inductor creates in an ac circuit.
Reactance modulator : an electronic circuit
whose capacitance or inductance changes in response to an audio input signal.
Receiver : a device that converts radio waves
into signals we can hear or see.
Receiver incremental tuning (RIT) : a transceiver
control that allows for a slight change in a receiver frequency without changing
the transmitter frequency. Some manufacturers call this a clarifier (CLAR)
control.
Receiver overload : interference to a receiver
caused by a strong RF signal that forces its way into the equipment. A signal
that overloads the receiver RF amplifier (front end) causes front-end overload. Receiver
overload is sometimes called RF overload.
Rectifier : an electronic component that allows
current to pass through it only in one direction.
Reflected power : non-radiated power dissipated
as heat when the transmitter is mismatched to the antenna or load.
Reflection : signals that travel by Line-of-sight
propagation are reflected by large objects like buildings.
Reflector : an element behind the driven element
in an Yagi and some other directional antennas.
Refract : to bend. Electromagnetic energy is
refracted when it passes through a boundary between different types of material.
Light is refracted as it travels from air into water or from water into air.
Repeater : an automatic relay station, generally in a high location,
which is used to increase the range of mobile and handheld FM
transmitter/receivers.
Repeater station : an amateur station that
automatically retransmits the signals of other stations.
Resistance : the ability to oppose an electric
current.
Resistor : any material that opposes a
current in an electrical circuit. An electronic component specifically designed
to oppose or control current through a circuit.
Resonant frequency : the desired operating
frequency of a tuned circuit. In an antenna, the resonant frequency is one where
the feed point impedance contains only resistance.\
Reverse patch : when a call is received on its incoming telephone line
this special autopatch rings over the air and may be answered by tone access.
RF : (Radio Frequency)
RF burn : a burn produced by coming in contact
with exposed RF voltages.
RF carrier : a steady radio frequency signal that
is modulated to add an information signal to be transmitted. For example, a
voice signal is added to the RF carrier to produce a Phone emission
signal.
RF envelope : the shape of an RF signal as
viewed on a oscilloscope.
RF ground : connection of amateur equipment to
earth ground to eliminate hazards from RF exposure and reduce RFI.
RFI : (Radio Frequency Interference)
RF overload : another term for receiver
overload.
RF radiation : waves of electronic and magnetic
energy. Such electromagnetic radiation with frequencies as low as 3 kHz and as
high as 300 GHz are considered to be part of the RF region.
RF safety : preventing injury or illness to
humans from the effects of radio frequency energy.
Rig : the radio amateur's term for a transmitter,
receiver, or transceiver.
Ripple : the amount of change between the
maximum voltage and the minimum voltage in a pulsating dc wave form.
RIT : (Receiver Incremental Tuning) fine-tuning
receive frequency without changing displayed or memory frequency.
Root-mean square (RMS) voltage : another name
for effective voltage. The term refers to the method of calculating the value.
Routine RF evaluation : a procedure required of
some Amateur Radio stations, to determine that the station meets the maximum
permissible exposure (MPE) limits established by FCC rules.
RST : a system of numbers used for signal
reports: R is readability, S is strength, and T is tone.
RTTY : (RadioTeleTYpe)
RX : (Receive)
TOP
S
S meter or Signal meter : a meter in a
receiver that shows the relative strength of a received signal.
S/N : (Signal to Noise radio)
Safety interlock : a switch that automatically
turns off ac power to a piece of equipment when the top cover is removed.
Scan : continually sweeping frequencies looking
for signals.
Scan edge : end and start frequencies for a
scanning range.
Scatter : several factors may cause some energy
from a radio signal to follow a path other than the idealized "straight
line". Scattering can take place from Earth's ionospheric and atmospheric
layers as well as objects in the wave path.
Schematic symbol : a drawing used to represent a
circuit component on a wiring diagram.
Scratch pad memory : temporary frequency memories
for quick access.
Secondary winding : the coil in a transformer
that is connected to the load.
Selectivity : the ability of a receiver to
separate two closely spaced signals.
Semi Duplex : an operation mode in which
transmissions and receptions are accomplished on different frequencies
alternatively.
Sensitivity : the ability of a receiver to detect
weak signals.
Separation (split) : the difference, in kHz, between the repeater's
transmit and receive frequencies. Conventional separations by amateur band are:
29 MHz - 100 kHz;
50 MHz - 1 MHz;
144 MHz - 600 kHz;
220 MHz - 1.6 MHz;
440 MHz - 5 MHz;
902 MHz - 13 MHz;
1270 MHz - 12MHz.
Series circuit : an electrical circuit in which
all the electrons must flow through every part of the circuit. There is only one
path for the electrons to flow.
Set mode : an operation used for radio. To set
less frequently used control features.
Shack : the room where an Amateur Radio operator
keeps his or her station equipment.
Short circuit : an electrical circuit in which
the current does not take the desired path, but finds a short cut instead. Often
current goes directly from the negative power supply terminal to the positive
one, bypassing the rest of the circuit.
Short-path communication : communication made
by pointing beam antennas in the direction indicated by the shorter
Great-circle path.
Sidebands : the sum or difference frequencies
generated when an RF carrier is mixed with an audio signal. Single-sideband
phone (SSB) signals have an upper sideband (USB - that part of the signal above
the carrier) and a lower sideband (LSB - that part of the signal below the
carrier). SSB transceivers allow operation on either USB or LSB.
Signal tracer : a test instrument that shows
the presence of RF or AF energy in a circuit. The signal tracer is used to trace
the flow of a signal through a multistage circuit.
Simplex : a mode of communication in which you take turns to transmit
and receive on the same frequency. A frequency set aside for non-repeater use.
Simplex operation : receiving and
transmitting on the same frequency.
Single-pole, double-throw (SPDT) switch : a
switch that connects one center contact to one of two other contacts.
Single-pole, single-throw (SPST) switch : a
switch that only connects one center contact to another contact.
Single sideband (SSB) phone : a common mode of
voice operation on the amateur bands. SSB is a form of Amplitude Modulation.
The amplitude of the transmitted signal varies with the voice signal variations.
Single-sideband, suppressed-carrier signal : a
radio signal in which only one of the two sidebands generated by amplitude
modulation is transmitted. The other sideband and the RF carrier signal are
removed before the signal is transmitted.
Single-sideband, suppressed-carrier, amplitude
modulation (SSB) : a technique used to transmit voice information in which
the amplitude of the RF carrier is modulated by the audio input, and the carrier
and one sideband are suppressed.
Skip zone : an area of poor radio communication,
too distant for ground waves and too close for sky waves.
Skywarn : trained volunteer storm spotters for
the National Weather Service.
Sky waves : radio waves that travel from an
antenna upward to the ionosphere, where they either pass through the ionosphere
into space or are refracted back to Earth.
Sky-wave propagation : the method by which radio
waves travel through the ionosphere and back to Earth. Sometimes called skip,
sky-wave propagation has a far greater range than Line-of-sight and Ground-wave
propagation.
SMA : (Sub-Miniature a connector) type of antenna
connector, used in VHF/UHF portable.
Solar flare : a large eruption of energy and
solar material from the surface of the sun.
Solar flux : radio energy coming from the sun.
Solar flux index : a measure of solar activity.
The solar flux is a measure of the radio noise on 2800 MHz.
SOS : a Morse code call for emergency
assistance.
SP : (SPeaker)
Space station : an amateur station located more
than 50 km above the Earth's surface.
Specific absorption rate (SAR) : a term that
describes the rate at which RF energy is absorbed into the human body. Maximum
permissible exposure (MPE) limits are based on whole body SAR values.
Speech processor : a device used to increase
the average power contained in a speech wave form. Proper use of a speech
processor can greatly improve the readability of a voice signal.
Splatter : a type of interference to stations on
nearby frequencies. Splatter occurs when a transmitter is overmodulated.
Split : a mode in which the transmit and receive
frequency is different.
Spurious emissions : signals from a transmitter
on frequencies other than the operating frequency.
Squelch (SQL) : a circuit within a radio that keeps the speaker silenced
(squelched) until the signal level exceeds a certain point, set by the squelch
control. Normally you set the squelch to just block out noise and allow signals
to pass.
SSTV : (Slow Scan TV) graphics communication
using narrow bandwidth.
Standing-wave ratio (SWR) : sometimes called
voltage standing wave ratio (VSWR). A measure of the impedance match between the
feed line and the antenna. Also, with a transmatch in use, a measure of the
match between the feed line from the transmitter and the antenna system. The
system includes the transmatch and the line to the antenna. VSWR is the ratio of
the maximum voltage to minimum voltage along the feed line. Also the ratio of
antenna impedance to feed line impedance when the antenna is purely resistive
load.
Station grounding : connecting all station
equipment to a good earth ground improves both safety and station performance.
Sub-audible tone : see CTCSS.
Sudden ionospheric disturbance (SID) : a black
out of HF sky-wave communications that occurs after a solar flare.
Sunspots : dark spots on the surface of the sun.
When there are few sun spots, long distance radio propagation is poor on the
higher frequency bands. When there are many sunspots, long distance HF
propagation improves.
Sunspot cycle : the number of sunspots
increases and decreases in a predictable cycle that lasts about 11 years.
Superheterodyne receiver : a receiver that
converts RF signals into an intermediate frequency before detecting them
(converting the signals to audio).
Suppressor capacitor : a capacitor (often
ceramic) connected across the transformer primary or secondary winding in a
power supply. These capacitors are intended to suppress any transient voltage
spikes, preventing them from getting through the power supply.
Switch : a device used to connect or disconnect electrical
contacts.
SWL : (Short Wave Listener)
SWR meter : a measuring instrument that can
indicate when an antenna system is working well. A device used to measure SWR.
TOP
T
Tactical call signs : names used to identify a
location or function during local emergency communications.
Tail - the brief signal transmitted by a repeater transmitter after
someone stops talking.
TCXO : (Temperature Compensated Crystal
Oscillator) heated crystal oscillator for better frequency stability.
Teleprinter : a machine that can convert
keystrokes (typing) into electrical impulses. The teleprinter can also convert
the proper electrical impulses back into text. Computers have largely replaced
teleprinters for amateur radioteletype work.
Television interference (TVI) : interruption of
television reception caused by another signal.
Temperature coefficient : a number used to show
whether a component will increase or decrease in value as it gets warm.
Temperature inversion : a condition in the
atmosphere in which a region of cool air is trapped beneath warmer air.
Temporary state of communications emergency : when
a disaster disrupts normal communications in a particular area, the FCC can
declare this type of emergency. Certain rules may apply for the duration of the
emergency.
Terminal : an inexpensive piece of equipment that
can be used in place of a computer in a packet radio station.
Thermal effects of RF energy : body tissue
changes that are directly related to heat production when RF energy is absorbed.
For example, in extreme cases at high levels of SAR, hyperthermia and
tissue damage can occur. It has been demonstrated that in extreme cases,
RF-induced heating in the eyes of laboratory animals can result in cataract
formation.
Third-party communications : messages passed from
one amateur to another on behalf of a third person.
Third-party communications agreement : an
official understanding between the United States and another country that allows
amateurs in both countries to participate in third-party communications.
Third-party participation : the way an unlicensed
person can participate in amateur communications. A control operator must ensure
compliance with FCC rules.
Ticket : a common name for an Amateur Radio
license.
Time averaging : transmitter power is averaged
over times of six minutes for controlled RF environments or thirty minutes for
uncontrolled RF environments for power density calculations to determine
exposure levels.
Time-out : to cause the repeater, or a repeater function, to turn off
because you have transmitted too long.
Time-out timer (TOT): a device that measures the length of
each transmission and causes the repeater or a repeater function
to turn off after a transmission has exceeded a certain length.
Timers are used to protect the machine from damage if a station
accidentally activates it for too long (as may happen if someone
sits on his radio, unknowingly depressing his transceiver's PTT
button) or to prevent operators from hogging the machine with
excessively lengthy transmissions.
TNC : 1) Terminal Node Controller, a modem for
data communication. 2) a type of antenna connector.
Tone pad : an array of 12 or 16 numbered keys that generate the
standard telephone dual-tone multi-frequency (DTMF) dialing signals.
Touch tone : trade mark of AT&T. See DTMF.
Transceiver : a radio transmitter and receiver
combined in one unit.
Transformer : mutually coupled coils used to
change the voltage level of an ac power source to one more suitable for a
particular circuit.
Transistor : a solid-state device made of three
layers of semiconductor material. See NPN transistor and PNP
transistor.
Translator (Linear translator) : a device used to directly convert and
retransmit a block of received frequencies.
Transmission line : the wires or cables used to
connect a transmitter or receiver to an antenna. Also called Feed line.
Transmit-receive (TR) switch : a mechanical
switch relay or electronic circuit used to switch an antenna between a receiver
and a transmitter in an amateur station.
Transmitter : a device that produces radio
frequency signals.
Transponder : the term used for a linear translator in a satellite.
Inverting transponder transmits received upper sideband as lower sideband.
Non-inverting transponder transmits received upper sideband as upper sideband.
Triggering : to activate a repeater by transmitting on its input
frequency (see also key up).
Troposphere : the region in the Earth's
atmosphere just above the Earth's surface and below the ionosphere.
Tropospheric bending : when radio waves are bent
in the troposphere, they return to Earth farther away than the visible
horizon.
Tropospheric ducting : a type of VHF propagation
that can occur when warm air overruns cold air (a temperature inversion).
TS : (Tuning Step) incremental steps.
TSQL : (Tone SQueLch) squelch function using sub
audible tones, selective call.
TVI : (TeleVision Interference)
Two-tone test : problems in a side-band
transmitter can be detected by feeding two audio tones into the microphone input
of the transmitter and observing the output on an oscilloscope.
TX : (Transmit)
TOP
U
UHF (ultra high frequency) : the region of the radio spectrum between
300 and 1000 MHz or 1 GHz.
Unbalanced line : feed line with one conductor at
ground potential, such as coaxial cable.
Uncontrolled environment : any area in which an
RF signal may cause radiation exposure to people who may not be aware of the
radiated electric and magnetic fields. The FCC generally considers members of
the general public and am amateur's neighbors to be in an uncontrolled RF
radiation exposure environment to determine the maximum permissible exposure
levels.
Unidentified communications or signals : signals
or radio communications in which the transmitting station's call sign is not
transmitted.
Uplink : (see Downlink) frequency that a user
transmits to the repeater or satellite.
Upper sideband (USB) : the common single-sideband
operating mode on the 20, 17, 15, 12, and 10 meter HF amateur bands, and all the
VHF and UHF bands.
UTC : (Universal Time Coordinated) a astronomical
time based on the Greenwich meridian (zero degrees longitude).
TOP
V
Varactor diode : a component whose capacitance
varies as the reverse bias voltage is changed.
Variable capacitor : a capacitor that can have
its value changed within a certain range.
Variable-frequency oscillator (VFO) : an oscillator
used in receivers and transmitters. The frequency is set by a tuned circuit
using capacitors and inductors. The frequency can be changed by adjusting the
components in the tuned circuit.
Variable resistor : a resistor whose value can be
adjusted over a certain range, without removing it from a circuit.
Vertical antenna : a common amateur antenna,
often made of metal tubing. The radiating element is vertical. There are usually
four or more radio elements parallel to or on the ground.
Vertical polarization : the antenna elements are vertical (used at
VHF/UHF for FM and repeater operation).
Vertically polarized wave : a radio wave that
has its electric lines of force perpendicular to the surface of the Earth.
VHF (Very High Frequency) : the region of the radio spectrum between
30 and 300 megahertz (MHz).
Visible horizon : the most distant point one can
see by line of sight.
Voice : any of the several methods used by
amateurs to transmit speech.
Voice communications : hams can use several voice
modes, including FM and SSB.
Voice-Operated Transmit (VOX) : circuitry that
activates the transmitter when the operator speaks into the microphone.
Volt (V) : the basic unit of electrical pressure
or EMF.
Voltage : the EMF or pressure that causes
electrons to move through an electrical circuit.
Voltmeter : a test instrument used to measure
voltage.
VSC : 1) Voice Scan Control. 2) Voice Squelch
Control.
TOP
W
Watt (W) : the unit of power in the
metric system. The watt describes how fast a circuit uses electrical energy.
Wattmeter : also called a power
meter, a test instrument used to measure the power output (in watts) of a
transmitter. A Directional Wattmeter measures both forward and
reflective power.
Wavelength : the distance a radio
wave travels in one RF cycle. The wavelength relates to frequency. Higher
frequencies have shorted wavelengths.
Weather alert : NOAA broadcast
station transmitting alert signals.
WFM : (Wideband FM)
TOP
X
X - beam antenna : a high
performance broad-band antenna that is ideal for radio operators with limited
space. The X-beam is a compact version of the 2 - element Yagi; its performance
equals or exceeds that of its conventional counterpart. Its name is derived from
its shape.
TOP
Y
Yagi antenna : the most popular type
of amateur directional (beam) antenna. It has one driven element and one or more
additional elements.
TOP
Z
Zeppelin antenna : a dipole
antenna used as an all-band radiator by using tuned open wire feed line. A
typical antenna of this type might be utilized from 80 through 10 meters. See
also J antenna.
TOP
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