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NAVEDTRA 14189A
RADIO-FREQUENCY COMMUNICATIONS PRINCIPLES ET2 BIBS MAR 2017
| Question | Answer |
|---|---|
| What year was the first official naval radio message sent from ship to shore? | 1899 |
| What year was the first radiotelephone used between ships? | 1916 |
| In what year were the first super-heterodyne receivers installed in the fleet? | 1931 |
| In what year were the first successful radio teletypewriter transmissions between ships completed? | 1944 |
| In what year di the first successful use of radiophoto (facsimile) occur? | 1945 |
| What refers to communications over a distance and includes any transmissions, emission, or reception of signs, signals, writings, images, or sounds? | telecommunications |
| What is the most important method the Navy has of communicating between widely separated forces? | radio |
| What was the first means of radio communications that had military and commercial importance? | radiotelegraphy |
| The Navy uses radio teletypewriter (rtty) mainly for high speed automatic communications across ocean areas and has normal speed operation of how many words per minute? | 100 |
| What is the process used to transmit photographs, charts, and other graphic information electronically? | facsimile (fax) |
| What is a combination of sets, unit, assemblies, subassemblies, and parts connected or associates together to perform a specific operational function or several functions? | system |
| What consists of a unit or units and the assemblies, subassemblies, and parts connected or associated together to perform a specific function? | set |
| What is a collection of units, assemblies, subassemblies, and parts? | group |
| What is an assembly or any combination of parts, subassemblies, and assemblies mounted together? | unit |
| What is a number of parts or subassemblies, or any combination thereof, joined together to perform a specific function? | assembly |
| What is one component or two or more components joined together? | part |
| What is the frequency range for the extremely high frequency (EHF) band? | 30GHz - 300GHz |
| What is the frequency range for the super high frequency (SHF) band? | 3GHz - 30GHz |
| What is the frequency range for the ultra high frequency (UHF) band? | 300MHz - 3GHz |
| What is the frequency range for the very high frequency (VHF) band? | 30MHz - 300MHz |
| What is the frequency range for the high frequency (HF) band? | 3MHz - 30MHz |
| What is the frequency range for the medium frequency (MF) band? | 300KHz - 3MHz |
| What is the frequency range for the low frequency (LF) band? | 30KHz - 300KHz |
| What is the frequency range for the very low frequency (VLF) band? | 3KHz - 30KHz |
| What is the frequency range for the extremely low frequency (ELF) band? | up to 300 Hz |
| What band has the ability to penetrate ocean depths to several hundred feet with little signal loss? | ELF |
| What type of transmission is normally considered a broadcast, that is, one-way transmission, no reply required? | VLF |
| What systems are established to communicate over long distance trunks or links between fixed terminals? | point-to-point |
| What is normally a message circuit between two points that are both switching centers or individual message distribution points? | trunk |
| What is a transmitter-receiver system connecting two locations? | Link |
| The naval communications system is broken down into what groups? | strategic and tactical |
| What type of communications are usually limited to a specific area of operation and are used to direct or report the movement of specific forces? | tactical |
| What mode is a method of operation in which telecommunication between stations takes place simultaneously in both directions using two separate frequencies? | full-duplex (fdx) |
| What is the type of operation in which one station transmits information on one or more channels directed to more than one station and/or unit? | broadcast (bc) |
| Message traffic is normally sent to the fleet by three methods: broadcast, intercept, and what else? | receipt |
| What provides authorized users with a means for exchanging classified information over communications security (COMSEC) circuitry or over other approved circuitry? | AUTOSEVOCOM |
| What was established for the purpose of integrating the critical intelligence communications (CRITICOMM) and the special intelligence communications (SPINTCOMM) networks into a single automated communications network? | DSSCS |
| What network provides a voice link between the Chief of Naval Operations (CNO) and all subordinate commands ashore, afloat, and airborne? | HICOM |
| What is the principle use of the continuous wave ? | radiotelegraphy |
| A CW transmitter requires for essential components. These are a generator, amplifier, keyer, and what else? | antenna |
| What is power the product of? | current and voltage |
| What refers to a sine wave quantity that has a frequency that is a submultiple of the frequency of some other sine wave quantity it helped make? | subharmonic |
| What are special power amplifiers that multiply the input frequency? | frequency multipliers |
| What is the elimination of the undesired portions of the signal? | suppression |
| What type of transmission is the most common communications mode used today? | single-sideband |
| What is generally used whenever special voice communications circuits are necessary between shore activities or between ships and shore activities because it is less susceptible to atmospheric interference than amplitude modulation? | single-sideband (SSB) |
| What is used extensively in naval communications to expand our traffic capabilities? | independent-sideband (ISB) |
| What four basic functions must a receiver perform in order to be useful? | reception, selection, detection, and reproduction |
| What occurs when a transmitted electromagnetic wave passes through the receiver antenna and induces a voltage in the antenna? | reception |
| What is the ability of the receiver to select a particular frequency of a station from all other station frequencies appearing at the antenna of the receiver? | selection |
| What is the action of separating the low (audio) frequency intelligence from the high (radio) frequency carrier? | detection |
| What is the action of converting the electrical signals to sound waves? | reproduction |
| What property is defined by the ability of a receiver to reproduce weak signals ? | sensitivity |
| What is the limiting factor of sensitivity? | noise |
| What is the degree of distinction made by the receiver between the desired signal and unwanted signals? | selectivity |
| What is the process used to tune two or more circuits with a single control? | ganged tuning |
| What are the only two fundamental sections of the FM receiver that are electrically different from the AM receiver? | discriminator and limiter |
| Which circuit in FM circuits is designed to respond to frequency shift variations? | discriminator |
| What is the variation in signal strength called at the receiver antenna? | Fading |
| What is an AGC voltage that is used to cause degeneration by driving the amplifiers toward cutoff referred to as? | reverse AGC |
| Which audio amplifier property determines the degree of amplification provided to different frequencies in the sound spectrum? | frequency response |
| Treble tones are defined as the audio frequencies above approximately what frequency? | 3,000 Hz |
| Bass tones are defined as the audio frequencies below approximately what frequency? | 300 Hz |
| Which circuits are used in situations where you must accurately control the frequency of an oscillator by some external signal? | automatic frequency control |
| Which circuit cuts off the output of a receiver when there is no input? | squelch |
| What is a signal-producing process through heterodyning and frequency selection? | frequency synthesis |
| What provides the capability to transfer remote control station functions and signals to transmitters? | transmitter transfer switchboard |
| What is the most widely used code in manual telegraphy? | Morse code |
| The interval between words is equal to how many dots in Morse code? | seven |
| The five unit code has been the most commonly used in modern printing telegraphy and is universally used in teletypewriter operation. This is also known as what code? | Baudot |
| What are the two basic modes of teletypewriter operation? | asynchronous and synchronous |
| What is the most common mode used in teletypewriter operation? | start-stop |
| What is the reciprocal of the time in seconds of the shortest signal element? | baud rate |
| How many words per minute is the defense communications system standard speed for teletypewriter operation? | 100 |
| Which type of circuits make use of the presence or absence of current flow to convey information? | neutral |
| Which two basic radio teletypewriter (ratt) system does the Navy use? | tone modulated and carrier frequency shift |
| Which colors are used on patch panels to identify whether that panel is used for passing secure or non-secure information? | red and black |
| Which type of equipment is used to encrypt and decrypt tty messages that require security handling? | cryptographic |
| What takes the rf signal passed on by the antenna filter and translates it to an audio signal? | radio receiver |
| Which type of communications circuit permits two-way communications between stations? | half-duplex |
| What is the simultaneous transmission of a number of intelligible signals (messages) in either or both directions called using only a single rf carrier? | multiplexing |
| Which two methods of multiplexing can be used? | time-division and frequency-division multiplexing |
| What is the normal voice speaking frequency range? | 100 to 3500 Hz |
| By multiplexing tty circuits, up to how many circuits may be carried in any one of the 3000 Hz multiplexed channels? | 16 |
| Which transmission method is used for transmitting still images over an electrical communications system? | facsimile |
| What are compromising emanations (ce) generally referred to as? | tempest |
| What includes all measures designed to protect transmission from interception, traffic analysis, and imitative deception? | transmission security |
| What occurs when a person comes into contact with a source of rf voltage in a manner that allows rf current to flow through the area of contact? | rf burn |
| Which device changes dc pulses to mark and space modulation for teletypewriter transmissions? | keyer |
| What changes an audio signal back to dc pulses during teletypewriter reception? | converter |
| Which device stores a teletypewriter message on a paper tape by punching Baudot coded messages into it? | perforator |
| What stores an incoming tty signal on paper tape? | reperforator |
| What is the reference color of equipment that passes classified information? | red |
| Which year was the first artificial satellite placed in orbit by the Russians? | 1957 |
| Score was the first satellite with the primary purpose of communications by the US in which year? | 1958 |
| Which year was the first regular satellite communications service used by the Navy? | 1960 |
| Which year was the Defense Communications Satellite Program (DSCP) initiated by the Secretary of Defense? | 1962 |
| Which type of satellite only reflects received radio signals back to earth? | passive |
| What amplifies signals received and then retransmits them back to earth? | repeater |
| In general terms, an orbit is either elliptical or which other shape? | circular |
| What is a period of orbit that approaches that of the earth called? | near synchronous |
| All satellites orbit the earth in which type of orbit? | elliptical |
| What is the point in the orbit called when it is the greatest distance from the center of the earth? | apogee |
| What is the angle between the equatorial plane of the earth and the orbital plane of the satellite called? | angle of inclination |
| A satellite orbiting in any plane not identical with the equatorial plane is in which type of orbit? | inclined |
| Which type of orbit is defined by a satellite orbiting in a plane that coincides with equatorial plane of the earth? | equatorial |
| Generally speaking, how many sizes of parabolic-type antennas are currently in use at earth terminal sites? | three |
| Which table provides the coordinates of a satellite or a celestial body at specific times during a given period? | ephemeris |
| What is the period of time called for one earth terminal to yield control to another as a satellite moves out of its area of coverage? | hand over |
| Which year did the Department of the Navy establish the Naval Space Command? | 1983 |
| Which year was the first DSCS Phase III satellite launched into orbit? | 1984 |
| What is the zone called where the satellite can be seen by both the up and down-link earth terminals? | zone of mutual visibility |
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nng7294
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