Electronics (Mike Jaroch)
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An acronym for RAdio Detecting And Ranging .
Airborne radar that measures the distance of the aircraft above the ground .
The space in front of a radar antenna where a target can be effectively detected or tracked. Defined by areas that contain half or more of the maximum power transmitted .
A detector that, in its simplest form, only needs to be capable of producing an
output when RF energy (reflected from a target) is present at its input .
RADAR DISTRIBUTION SWITCHBOARD
An electrical switching panel used to connect inputs from any of several radars to repeaters (indicators) .
Time interval (12.36 microseconds) for RF energy to travel out from a radar to a target and back to the radar; radar nautical mile .
RADAR TEST SET
A combination of several test circuits and equipment used to test various
characteristics of a radar .
The electromagnetic field that radiates from an antenna and travels through space .
The losses that occur when magnetic lines of force about a conductor are
projected into space as radiation and are not returned to the conductor as the cycle alternates .
A plot of the radiated energy from an antenna .
The resistance that if inserted in place of the antenna would consume the
same amount of power as that radiated by the antenna .
The term describing teletypewriter, voice, telegraphic, and facsimile
RADIO FREQUENCY (RF)—(1) Any frequency of electromagnetic energy capable of propagation into space . (2) The frequencies that fall between 3 kilohertz and 300 gigahertz used for radio communications .
RADIO FREQUENCY CARRIER SHIFT
The system that uses a keyer to shift a radio frequency signal above or below an assigned frequency. These shifts correspond to marks and spaces .
The boundary beyond the natural horizon in which radio waves cannot be propagated over the earth's surface .
RADIO SET CONTROL UNIT
Equipment used to remotely control certain transmitter and receiver
(1) A form of radiant energy that can neither be seen nor felt. (2) An electromagnetic wave that is generated by a transmitter .
Also called BINARY POINT, OCTAL POINT, DECIMAL POINT, and so forth, depending on the number system .
The length of a straight line between a radar set and a target  .
A movable vertical pulse on an A-scope or a ring on a PPI scope used to measure the range of an echo or to calibrate the range scale .
Ability of a radar to distinguish between targets that are close together .
On an A-scope sweep, a vertical displacement used to measure the range of an echo .
A movable gate used to select radar echoes from a very short range interval .
A radar display on which slant range is shown along the X axis and height along the Y axis .
The several upper limits a meter will measure as selectable by a switch or by jacks; for example, a voltmeter may have ranges of 1 volt, 2.5 volts, 10 volts, 25 volts, and 100 volts .
A longitudinal wave that has been expanded or rarefied (made less dense) as it
moves away from the source .
A gyro used to detect and measure angular rates of change .
The value obtained when one number is divided by another. This value indicates the relative proportions of the two numbers .
A detector that uses a double-tuned transformer to convert the instantaneous
frequency variations of the FM input signal to instantaneous amplitude variations .
RATIO OF TRANSMITTED POWERS
The power ratio (FSK versus AM) that expresses the overall improvement of FSK transmission when compared to AM under rapid-fading and high-noise conditions
Time constant of a resistor-capacitor circuit; equal in seconds to the resistance value in ohms multiplied by the capacitance value in farads  .
An RC circuit in which the output is taken from the resistor .
A filter used in applications where load current is low and constant, and voltage regulation is not necessary .
An RC circuit in which the output is taken from the capacitor .
A circuit containing resistance and capacitance arranged in a particular manner to perform a specific function .
An oscillator in which the frequency is determined by resistive and capacitive
The opposition offered to the flow of an alternating current by the inductance,
capacitance, or both, in any circuit .
A low-noise amplifier that uses a nonlinear variable reactance as the active
element instead of a variable resistance. Also called a parametric amplifier .
A tube connected in parallel with the tank circuit of an oscillator. Provides a signal that will either lag or lead the signal produced by the tank .
An FM modulator that uses a reactance tube in parallel with the oscillator tank circuit .
(1) The object that responds to the wave or disturbance. Same as DETECTOR . (2) Equipment that converts electromagnetic energy into a visible or an audible form . (3) In radar, a unit that converts RF echoes to video and/or audio signals .
(1) The degree to which a receiver can usefully detect a weak signal. (2)
The lower limit of useful signal input to the receiver .
RECEIVER TRANSFER SWITCHBOARD
Equipment used to transfer receiver audio outputs to remote control station audio circuits .
The device used to pick up the RF signal from space .
See OUTPUT END .
The instant when an electromagnetic wave passes through a receiver antenna and induces a voltage in that antenna .
(OF A QUANTITY)—The value obtained by dividing the number 1 by that quantity .
The property of interchangeability of the same antenna for transmitting and receiving  .
In a radar, the time interval between the end of the transmitted pulse and the time when echo signals are no longer attenuated by the tr gap .
A graph in which straight-line axes (horizontal and vertical) are perpendicular .
A device used to convert ac to pulsating dc   .
The reference color of equipment that passes classified information. It normally refers to patch panels .
The position of zero displacement in a wave .
A point in a circuit to which all other points in the circuit are compared .
(1) The wave that reflects back from a medium. (2) The wave moving back to the source from the termination of a transmission line after reflection has occurred .
In radar a air or surface contact that provides an echo .
Waves that are neither transmitted nor absorbed, but are reflected from the
surface of the medium they encounter .
The parasitic element of an array that causes maximum energy radiation in a direction toward the driven element .
A klystron with a reflector (repeller) electrode in the place of a second resonant cavity used to redirect the velocity-modulated electrons back through the cavity that produced the modulation . (2) A microwave oscillator that is tuned by changing the repealer voltage .
The changing of direction of a wave as it leaves one medium and enters another medium of a different density  .
In a wave-transmission medium, the ratio between the phase velocity in free
space and in the medium  .
See FEEDBACK .
A detector circuit that produces its own oscillations, heterodynes them
with an incoming signal, and deflects them .
The process by which a portion of the output signal of an amplifying
device is fed back in phase to reinforce the input. Also called POSITIVE FEEDBACK  .
The section in a basic power supply that maintains the output of the power supply at a constant level in spite of large changes in load current or input line voltage  .
Bearing of a target measured in a clockwise direction from "dead ahead" of a
ship or plane .
An electromagnetic device with one or more sets of contacts that change position by the magnetic attraction of a coil to an armature .
A measure of the opposition that a material offers to magnetic lines of force .
An electron tube in which the control grid wires are farther apart at the
centers than at the ends. This arrangement allows the tube to amplify large signals without being driven into cutoff. This tube is also called a VARIABLE-MU TUBE .
(1) Another name for an active satellite . (2) Also, a common name for remote radar indicators.
Sometimes called a REFLECTOR. An electrode in a reflex klystron with the primary purpose of reversing the direction of the electron beam .
Equipment that converts the incoming TTY signal and stores it on paper tape .
The process of converting electrical signals to sound waves. This sound is speech, music, and so on .
The mechanical force tending to separate bodies having like electrical charges or like magnetic polarity .
The reception and retransmission of radio waves that is caused by turbulence in the troposphere .
Magnetism remaining in a substance after removal of the magnetizing force
(1) The opposition a device or material offers to the flow of current. The effect of resistance is to raise the temperature of the material or device carrying the current. (2) A circuit element designed to offer a predetermined resistance to current flow. A resistance of 1 ohm will allow a current of 1 ampere to flow through it when a potential of 1 volt is applied. .
See SPECIFIC RESISTANCE. The reciprocal of conductivity .
The electrical component that offers resistance to the flow of current. It may be a coil of fine wire or a composition rod .
A rotary, electromechanical device used to perform trigonometric computations by varying the magnetic couplings between its primary and secondary windings. It is generally used in circuits that solve vector problems, such as analog computers and conversion equipment. The resolver solves three different type problems: (1) Resolution - separating a vector into two mutually perpendicular
components; (2) Composition - combining two components of a vector to produce a vector sum; and (3) Combination - the process of resolution and composition taking place simultaneously .
The condition in a circuit containing inductance and capacitance in which the inductive reactance is equal and opposite to the capacitive reactance. This condition occurs at only one frequency and the circuit in that condition is said to be in resonance   .
See ECHO BOX .
A circuit that contains both inductance and capacitance and is resonant at one
frequency (XL = XC) .
That frequency in a given resonant circuit at which the inductive and
capacitive reactance values are equal and cancel each other .
A transmission line that has standing waves of current and voltage .
The carrier frequency during the constant-amplitude portions of a phase
modulation signal .
See REFERENCE LINE .
(RT)—The time when there is no pulse; nonpulse time .
RESULTANT MAGNETIC FIELD
The magnetic field produced in a synchro by the combined effects of the three stator magnetic fields .
The ability of a material to retain its magnetism .
The RF signal reflected back from a radar target; echo .
The multiple reflections of sound waves .
The type of AGC that causes an amplifier to be driven toward cut-off .
An external voltage applied to a diode or semiconductor junction to reduce the flow of electrons across the junction. Also called BACK BIAS  .
RF (RADIO FREQUENCY) AMPLIFIER—An amplifier designed to amplify signals with frequencies between 10 kilohertz (10 kHz) and 100,000 megahertz (100,000 MHz) .
RF RADIATION HAZARD
A health hazard caused by exposure to electromagnetic radiation or high-
energy particles (ions). Abbreviated RADHAZ .
RF (RADIO FREQUENCY) TRANSFORMER—A transformer specially designed for use with RF (radio frequencies). An RF transformer is wound onto a tube of nonmagnetic material and has a core of either powdered iron or air .
The symbol used to express the resistance between the grid and the cathode of an electron tube .
A variable resistor used for the purpose of adjusting the current in a circuit  .
Greek letter "rho" (ρ). Used in the field of electricity and electronics to represent the specific resistance of a substance .
A diamond-shaped antenna used widely for long-distance, high-frequency
transmission and reception .
RIGID COAXIAL LINE
A coaxial line consisting of a central insulated wire (inner conductor) mounted
inside of a tubular outer conductor .
The tendency of the spin axis of a gyro wheel to remain in a fixed direction in space if no force is applied to it .
In radar, the time during which the output of an echo box remains above a specified level .
RF oscillations caused by shock excitation of a resonant circuit or cavity .
The frequency of the ripple current. In a full-wave rectifier it is twice the input-line frequency .
The alternating component of unidirectional voltage. (This component is small
compared to the direct component.) 
An RL circuit in which the output is taken from the inductor .
An RL circuit in which the output is taken from the resistor .
An electrical circuit that has the properties of resistance, inductance, and capacitance .
Abbreviation of root mean square .
ROOT MEAN SQUARE
(RMS)—The equivalent heating value of an alternating current or voltage, as
compared to a direct current or voltage. It is 0.707 times the peak value of a sine wave .
A spark gap, similar to a mechanically driven rotary switch, used to discharge a pulse-forming network .
A multicontact switch with contacts arranged in a circular or semicircular manner .
The magnetic field in a multiphase ac motor that is the result of field windings being energized by out-of-phase currents. In effect, the magnetic field is made to rotate electrically rather than mechanically .
A joint that permits one section of a transmission line or waveguide to rotate
continuously with respect to another while passing energy through the joint. Also called a rotary coupler .
(1) The revolving part of a rotating electrical machine. The rotor may be either the field or the armature, depending on the design of the machine . (2) The rotating member of a synchro that consists of one or more coils of wire wound on a laminated core. Depending on the type of synchro, the rotor functions similarly to the primary or secondary winding of a transformer .
The symbol used to represent the resistance between the cathode and plate of a tube .
The teletypewriter condition where the type hammer constantly strikes the type box but does not print or move across the page .