Section-b: Principles of Communications: Key Topic #7: Radio Spectrum:

7B1 What is the frequency range for Medium Frequency?

A. 10-30 MHz

B. 1,000-10,000 kHz

C. 300-3,000 kHz

D. 30-300 kHz

7B2 What is the frequency range for High Frequency?

A. 300-3,000 kHz

B. 30-300 MHz

C. 10-30 MHz

D. 3-30 MHz

7B3 What is the frequency range for Very High Frequency?

A. 30-300 MHz

B. 3-30 MHz

C. 300-3,000 kHz

D. 10-30 MHz

7B4 What is the frequency range for Ultra High Frequency?

A. 3-30 MHz

B. 300-3,000 MHz

C. 30-300 MHz

D. 10-30 MHz

7B5 What is the frequency range for Super High Frequency?

A. 30-300 GHz

B. 3-30 GHz

C. 300-3,000 MHz

D. 30-300 MHz

7B6 What is the primary frequency range for terrestrial communications using skywave propagation?

A. 300-3,000 kHz

B. 30-300 MHz

C. 3-30 MHz

D. 10-30 MHz

Answers: 7B1 - C 7B2 - D 7B3 - A 7B4 - B 7B5 - B 7B6 - C

Section-b: Principles of Communications: Key Topic #8: Frequency Bands:

8B1 Which of the following systems is most susceptible to fading or static interference?

A. Inmarsat

B. HF SITOR (NBDP)

C. DSC on channel 70

D. VHF ARQ

8B2 Which system is most likely to be affected by atmospheric disturbances?

A. VHF DSC

B. Inmarsat

C. MF/HF radiotelephony

D. SafetyNET^TM

8B3 Which of the following systems is least susceptible to fading or static interference?

A. HF SITOR (NBDP)

B. MF-HF DSC Controller

C. VHF ARQ

D. Inmarsat

8B4 Which of the following systems is least susceptible to atmospheric disturbances?

A. Inmarsat

B. NAVTEX

C. MF SITOR (NBDP)

D. HF SITOR (NBDP)

8B5 Which of the following frequency bands would most likely provide reliable communications between two stations that are 100 miles (160 km) apart?

A. The Low Frequency (LF) band.

B. The High Frequency (HF) band.

C. The Very High Frequency (VHF) band.

D. The Medium Frequency (MF) band.

8B6 Which system has the least effective radius of operation?

A. VHF DSC

B. HF SITOR (NBDP)

C. MF SITOR (NBDP)

D. NAVTEX

Answers: 8B1 - B 8B2 - C 8B3 - D 8B4 - A 8B5 - D 8B6 - A

Section-b: Principles of Communications: Key Topic #9: Modulation, Demodulation, am, fm:

9B1 What statement best describes modulation?

A. Imposing intelligence onto a radio carrier signal.

B. Changing mark-space to 1 and 0.

C. Adjusting the frequency to the optimum band for long distance communications.

D. Converting the carrier from a low frequency to a higher frequency.

9B2 What statement best describes demodulation?

A. Detuning the receiver to remove interfering signals.

B. Extracting intelligence from the radio carrier signal.

C. Removing atmospheric noise from the signal.

D. Separating the TELEX signals from the voice signals.

9B3 Which statement best describes amplitude modulation?

A. The character data from the terminal is changed to audio tones.

B. The frequency is varied in synchronization with the modulating signal.

C. The amplitudes in the sideband(s) changes but the radio carrier frequency remains constant.

D. The amplitude of the carrier is changed but there is still only a single frequency being transmitted.

9B4 What is the emission designation for MF-HF voice signals?

A. F1B

B. J2B

C. F3E

D. J3E

9B5 Which statement best describes frequency modulation?

A. The information signal changes the radio carrier frequency but the amplitude remains constant.

B. Both the amplitude and frequency are changed by the modulating signal.

C. Frequency modulation is subject to interference by atmospheric noise.

D. High level mixing of the final amplifier signal and the information signal.

9B6 What is the emission designation for VHF-FM?

A. F3C

B. F3E

C. J2B

D. H3E

Answers: 9B1 - A 9B2 - B 9B3 - C 9B4 - D 9B5 - A 9B6 - B