MOD 17 1,2,3 Flashcards Preview

2015 > MOD 17 1,2,3 > Flashcards

Flashcards in MOD 17 1,2,3 Deck (85)
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Q1. What are the two types of electrical communications?

A1. Radio and wire.

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Q2. What is the main advantage of radiotelegraph communications?

Reliability

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Q3. Why is radiotelephone one of the most useful methods of military communications?

A3. It is direct, convenient and easy to use.

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Q4. What are the disadvantages of radiotelephone communications?

A4. Static, enemy interference or a high local noise level.

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Q5. What is the main use of a radio teletypewriter?

A5. High speed automatic communications across ocean areas.

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Q6. What is facsimile?

A6. The process used to transmit photographs, charts and other graphic information electronically.

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Q7. A system is subdivided into what levels?

A7. Set, group, unit, assembly, subassembly, and part.

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Q8. In the example 1A6CR3, what is the assembly designator?

A6

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Q9. he majority of vlf transmitters are used for what purpose?

A9. Fleet communications or navigation.

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Q10. Today the Navy uses lf communications as a segment of what operational system?

A10. Fleet Multichannel Broadcast System.

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Q11. Why does the Navy only use the upper and lower ends of the mf band?

A11. Due to the commercial broadcast (AM) band.

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Q12. What are the four general types of communications services in the hf band?

A12. Point-to-point, ship-to-shore, ground-to-air, and fleet broadcast.

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A message transmitted on several frequencies at the same time is an example of what type of transmission?

A13. Frequency-diversity.

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Q14. Physically separating receive antennas is an example of what technique?

A14. Space-diversity.

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Q15. When using frequencies above 30 megahertz, you are normally limited to using what range?

A15. Line of sight.

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Q16. The naval communications system is made up of what two groups of communications?

A16. Strategic and tactical.

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Q17. What are the five most prominent communications modes of operation?

A17. Simplex, half-duplex, semiduplex, duplex, and broadcast.

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Q18. What four switched networks are part of the defense communications system?

A18. AUTOVON, AUTOSEVOCOM, AUTODIN, and DSSCS.

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Q19. What two elements support only designated Navy requirements?

A19. HICOM and NORATS.

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Q1. What are the four basic transmitter types?

A1. Am, fm, cw, ssb.

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Q2. What is the function of the oscillator in a cw transmitter?

A2. It generates an rf carrier at a given frequency within required limits.

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Q3. What is the final stage of a transmitter?

A3. Power amplifier.

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Q4. What purpose does a microphone perform in an AM transmitter?

A4. It converts audio (sound) into electrical energy.

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Q5. In an fm transmitter, when does an oscillator generate only a steady frequency?

A5. When no modulation is present.

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Q6. What is a harmonic?

A6. It is an exact multiple of the basic or fundamental frequency.

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Q7. If the fundamental frequency is 200 megahertz, what is the third harmonic?

A7. 600 megahertz.

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Q8. Why are frequency multipliers used?

A8. To obtain higher carrier frequencies.

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Q9. What are two advantages of ssb transmission?

A9. It saves power and frequency bandwidth.

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Q10. What is the purpose of an order-wire circuit?

A10. For operator-to-operator service messages and frequency changes.