113 Technical Fundamentals Flashcards
Ehf Shf Uhf Vhf Hf Mf Lf Vlf Ulf Slf Elf
Ehf 30-300 GHz Shf 3-30 GHz Uhf 300 MHz- 3 GHz Vhf 30-300 MHz Hf 3-30 MHz Mf 300 KHz- 3 MHz Lf 30-300 KHz Vlf 3-30 KHz Ulf 300 Hz- 3 KHz Slf 30-300 Hz Elf 3-30 Hz
Frequency
number of cycles per second, measured in Hz
Wavelength
spatial period of the wave- the distance over which the wave’s shape repeats
Ducting
trapping of an RF wave between 2 layers of the earth’s atmosphere or between an atmospheric layer and earth
Refraction
change in the direction of the wave
Multiplexing
a process where multiple analog message signals or digital data streams are combined into one signal over a shared medium
Modulation/Demodulation
modulation is the process of conveying a message signal
demodulation is the act of extracting the original information-bearing signal from a modulated carrier wave
Bandwidth
a measure of the width of a range of frequencies, measured in Hz
Radio Waves
type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light
Propagation
the behavior of radio waves when they are transmitted, or propagated, from one point on Earth to another, or into various parts of the atmosphere
Azimuth Angle
horizontal angle measured clockwise from a north base line or meridian
Elevation Angle
angular height of the sun in the sky measured from the horizontal
USB
Upper Sideband- the signal components above the carrier frequency
LSB
Lower Sideband- the signal components below the carrier frequency
CW
Continuous wave- an electromagnetic wave of constant amplitude and frequency
AM
Amplitude Modulation- a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave
FM
Frequency Modulation- conveys information over a carrier wave by varying its frequency
PRI
Pulse Repetition Interval- the reciprocal of PRF is called PRT, PRI, or IPP, which is the elapsed time from the beginning of one pulse to the beginning of the next pulse
RF
Radio Frequency- frequency at which radar operates
BW
Bandwidth- difference between the upper and lower cutoff frequencies of a radar receiver, typically measured in Hz
PW
Pulse Width- duration of the pulse
SCAN
the movement of a radar beam as it searches for objects
Bearing
the direction of the line of sight from the radar antenna to the contact
Azimuth
compass bearing
Elevation
the angle between the horizontal plane and the LOS, measured in the vertical plane
Air Search
maintain 360 degree surveillance from the surface of high altitudes, and to detect and determine ranges and bearings of aircrafts targets over relatively large areas
Surface search
maintain 360 degree surveillance of the surface
Fire Control
RADAR which is designed specifically to provide information to a fire-control system in order to calculate a firing solution
OPELINT
locations and readiness
TECHELINT
capabilities and limitations
Half-duplex
provides for comms in both directions, but only in one direction per time
Duplex
composed of two connected parties or devices that can communicate with one another in both directions
Simplex
comms in one direction at one time, you cannot send if you are receiving
