113 Technical Fundamentals

Front 1

113.1-2 Define the Extremely High Frequency (EHF) band range and communication capabilities of transmissions.

Back 1

30 - 300GHz (SATCOM)

-SATCOM

Front 2

113.1 Define the Super High Frequency (SHF) band range and communication capabilities of transmissions.

Back 2

3 - 30GHz (RADAR, SATCOM)

-LOS, unaffected by static.

Front 3

113.1-2 Define the Ultra High Frequency (UHF) band range and communication capabilities of transmissions.

Back 3

300MHz - 3GHz (Tactical Voice/Data)

-LOS, ideal for ship to shore.

Front 4

113.1-2 Define the Very High Frequency (VHF) band range and communication capabilities of transmissions.

Back 4

30 - 300MHz (Tactical Voice, FM/HAM Radio)

-LOS, will penetrate the atmosphere.

Front 5

113.1-2 Define the High Frequency (HF) band range and communication capabilities of transmissions.

Back 5

3 - 30MHz (Long Range Terrestrial Radio)

-Easily modulated, dependent upon radio wave refraction in the ionosphere.

Front 6

113.1-2 Define the Medium Frequency (MF) band range and communication capabilities of transmissions.

Back 6

300KHz - 3MHZ (Intl. Distress Freqs., S&R, AM Radio)

-Capable of long distances over water and short-hauls over land.

Front 7

113.1-2 Define the Low Frequency (LF) band range and communication capabilities of transmissions.

Back 7

30 - 300KHz (Fleet Multi-channel Broadcast)

-Stable, not affected by ionospheric disturbances.

Front 8

113.1-2 Define the Very Low Frequency (VLF) band range and communication capabilities of transmissions.

Back 8

3 - 30KHz (Timing/Navigation/Synchronization)

-Provides a highly reliable path for communications in northern latitudes as well as over and under all oceans and seas of the world.

Front 9

113.1-2 Define the Extremely Low Frequency (ELF) band range and communication capabilities of transmissions.

Back 9

<= 3 KHz (Submarine PLSO Broadcast)

-Capable of penetrating ocean depths of several hundred feet with minimal signal loss.

Front 10

113.2 Define the Voice Frequency communication capabilities of transmission

Back 10

-Capable of penetrating the earth.

Front 11

113.3 Define Frequency

Back 11

The number of cycles that occur in one second, (Hz).

Front 12

113.3 Define Wavelength

Back 12

The distance from any point on a cycle to the corresponding point on the next cycle.

Front 13

113.3 Define Ducting

Back 13

Trapping of an RF wave between two layers of the earth’s atmosphere or between an atmospheric layer and the earth.

Front 14

113.3 Define Refraction

Back 14

The bending of RF waves as they pass through mediums of different density.

Front 15

113.3 Define Multiplexing

Back 15

A method for simultaneous transmission of two or more signals over a common carrier wave.

Front 16

113.3 Define Modulation/Demodulation

Back 16

The ability to impress intelligence upon a medium, such as radio waves. Demodulation is the process of reversing modulation.

Front 17

113.3 Define Bandwidth

Back 17

The section of the frequency spectrum that specific signals occupy.

Front 18

113.3 Define Keying

Back 18

Changing the characteristic of a signal by opening and closing a key. Can be Frequency (FSK) or Phase (PSK).

Front 19

113.3 Define Azimuth Angle

Back 19

Angle measured clockwise from true north in the horizontal plane (True North). May be easier understood as the bearing of an object in relation to a radar.

Front 20

113.3 Define Elevation Angel

Back 20

Angle between the horizontal plane and the line of sight, measured in the vertical plane. May be easier understood as the height of an object in relation to a radar.

Front 21

113.4 Discuss layers in terms of what it means in relation to the atmosphere.

Back 21

atmospheric regions with different temperatures and density.

Front 22

113.4 Discuss the Troposphere in terms of what it means in relation to the atmosphere.

Back 22

(surface - 3.7 miles) almost all weather conditions occur in this layer which can greatly affect radio transmissions.

Front 23

113.4 Discuss the Stratosphere in terms of what it means in relation to the atmosphere.

Back 23

(3.7 - 31.1 miles) near constant temperature and minimal water vapor with little to no effect on radio waves.

Front 24

113.4 Discuss the Ionosphere in terms of what it means in relation to the atmosphere.

Back 24

(31.1 - 250 miles) consists of 4 cloud like sub-layers (D, E, F1 and F2) enabling radio wave propagation to great distances around the earth making it the most important region of the atmosphere for long distance point-to-point communications.

Front 25

113.4 Discuss Frequency in terms of what it means in relation to the atmosphere.

Back 25

For successful communications between any two specified locations at any given time, there is a maximum frequency, a lowest frequency, and an optimum frequency that can be used.

Front 26

113.4 Discuss Radio Waves in terms of what it means in relation to the atmosphere.

Back 26

The influence exerted on radio waves by the Earth’s atmosphere adds many new factors to complicate what at first seems to be a relatively simple problem. These complications are due to a lack of uniformity within the Earth’s atmosphere. Atmospheric conditions vary with changes in height, geographical location, and even with changes in time (day, night, season, year).

Front 27

113.4 Discuss Propagation in terms of what it means in relation to the atmosphere.

Back 27

The path that a refracted wave follows to the receiver depends on the angle at which the wave strikes the ionosphere.

Front 28

113.5 Describe the following modulation type Upper Sideband (USB) and its common usage.

Back 28

All the sum frequencies above the carrier are spoken of collectively as the UPPER SIDEBAND. Used in HAM Radio.

Front 29

113.5 Describe the following modulation type Lower Sideband (LSB) and its common usage.

Back 29

All difference frequencies below the carrier, also considered as a group, are called the LOWER SIDEBAND. Used in HAM Radio.

Front 30

113.5 Describe the following modulation type Carrier Wave (CW) and its common usage.

Back 30

A radio wave of a constant amplitude, phase and constant frequency. Morse Code.

Front 31

113.5 Describe the following modulation type Amplitude Modulation (AM) and its common usage.

Back 31

Any method of varying the amplitude of a carrier wave in accordance with the intelligence being transmitted. Shortwave/ Talk radio.

Front 32

113.5 Describe the following modulation type Frequency Modulation (FM) and its common usage.

Back 32

Angle modulation in which the frequency (angular rate) of the carrier wave is caused to vary in accordance with the instantaneous amplitude variations of the modulating wave. Music and complex communications.

Front 33

113.6 Define the following term PRI as it applies to RADAR

Back 33

Pulse Repetition Interval. The time between a point on the pulse to the identical point on the next pulse. Reciprocal of PRF.

Front 34

113.6 Define the following term PRF as it applies to RADAR

Back 34

Pulse Repetition Frequency. Number of pulses radiated in one second given in Hz or pulse-per-second (PPS).

Front 35

113.6 Define the following term RF as it applies to RADAR

Back 35

Radio Frequency. Invisible waves of electromagnetic energy. Frequency of unmodulated input.

Front 36

113.6 Define the following term BW as it applies to RADAR

Back 36

Beamwidth. Width of a radar beam measured between half power points.

Front 37

113.6 Define the following term CW as it applies to RADAR

Back 37

Continuous Wave. A RADAR of constant amplitude, phase, and frequency. Uses the Doppler Effect.

Front 38

113.6 Define the following term PW as it applies to RADAR

Back 38

Pulse Width. The time between the leading and trailing edges of a pulse.

Front 39

113.6 Define the following term Scan as it applies to RADAR

Back 39

Systematic movement of a radar beam to cover a definite pattern or area in space.

Front 40

113.6 Define Bearing/Azimuth as it applies to RADAR

Back 40

Angle measured clockwise from True North in the horizontal plane.

Front 41

113.6 Define Elevation as it applies to RADAR

Back 41

The angle between the horizontal plane and the line-of-sight. (Altitude).

Front 42

113.7 Discuss Air Search RADAR.

Back 42

Air Search - Detect and determine the position, course, and speed of air targets in a relatively large area.
Types: AN/SPS-40, SPS-48, SPS-49
Maximum range of air-search radar can exceed 300 miles, and the bearing coverage is a complete 360-degree circle.
Used as early-warning devices because they can detect approaching enemy aircraft or missiles at great distances.

Front 43

113.7 Discuss Surface Search RADAR.

Back 43

Surface Search - Used to detect the presence of surface craft and low flying aircraft and to determine their presence. Used extensively as a navigational aid in coastal waters and in poor weather conditions.
Types: AN/SPS-55, SPS-67
Two Primary Functions
The detection and determination of accurate ranges and bearings of surface objects and low-flying aircraft.
To maintain a 360-degree search pattern for all objects within line-of-sight distan

Front 44

113.7 Discuss Fire Control RADAR.

Back 44

Fire Control - Usually produce a very narrow, circular beam.
Types: AN/MK-92, MK-95, AN/SPQ-9
Three Phases
Designation Phase - RADAR is directed to the general location of the desired target because of the narrow-beam pattern.
Acquisition Phase - RADAR system searches a small volume of space in a prearranged pattern until the target is located.
Tracking Phase - Once the target is located, the RADAR system automatically follows all target motions. The RADAR system is said to be locked on to the target during track phase.

Front 45

113.8 Explain OPELINT

Back 45

Operationally relevant information such as the location, movement, employment, tactics, and activity of foreign non communications emitters and their associated weapon systems.

Front 46

113.8 Explain TECHELINT

Back 46

Technical aspects of foreign non communications emitters such as signal characteristics, modes, functions, associations, capabilities, limitations, vulnerabilities, and technology levels.

Front 47

113.9 Define Half Duplex

Back 47

The half-duplex (hdx) mode has one-way flow of information between terminals. Technical arrangements often permit transmission in either direction, but not simultaneously.

Front 48

113.9 Define Full Duplex

Back 48

The full-duplex (fdx) mode is a method of operation in which telecommunications between stations takes place simultaneously in both directions using two separate frequencies.

Front 49

113.9 Define Simplex

Back 49

The simplex (splx) mode uses a single channel or frequency to exchange information between two or more terminals. Communications is in one direction only.