GMDSS Radio Theory and Operation
Midterm (Cal Maritime) UPDATED
ACTUAL Exam Questions and CORRECT
Answers
How many sidebands are present in the J3E mode? - CORRECT ANSWER - One upper
sideband.
A vertical quarter wave antenna with a good ground connection will: - CORRECT
ANSWER - Radiate omni-directionally.
Communications with an emission of F1B/J2B would typically have a channel spacing of: -
CORRECT ANSWER - 0.5 kHz
Which emission mode occupies the most bandwidth? - CORRECT ANSWER - F3E
Which statement best describes amplitude modulation? - CORRECT ANSWER - The
amplitudes in the sideband(s) changes but the radio carrier frequency remains constant.
What is the purpose or function of the antenna coupler? - CORRECT ANSWER -A
Electrically matching the antenna system to the transmit frequency.
B. Changing the overall wavelength of the antenna system (in addition to the fixed length whip.)
C. Enabling maximum transmitted signal on the band chosen by the operator.
For RF communications, "bandwidth" is best defined as: - CORRECT ANSWER - The
portion of the radio spectrum consumed by a particular emission selection and modulation
technique.
A ship has been communicating effectively on 16 MHz during daylight hours with a shore
station at a distance of 3500 miles. Toward late afternoon and evening what effect would be
, noticed? - CORRECT ANSWER - Communications should gradually deteriorate and
become impossible on this frequency at night.
What is the frequency range for Super High Frequency? - CORRECT ANSWER - 3-30
GHz
(3000000kHz-300000000kHz)
What would be the most appropriate HF bands for communicating from San Francisco to Taiwan
or the Philippines? - CORRECT ANSWER - 16 or 22 MHz when daylight at each end and
8 MHz when dark at each end.
What statement best describes modulation? - CORRECT ANSWER - Imposing
intelligence onto a radio carrier signal.
At mid-night, what would be the best choice in attempting to communicate, using SITOR
(NBDP) with a shore station some 800 miles distant? - CORRECT ANSWER - HF bands
A VHF frequency channel pair of TX 157.200 MHz and RX 161.800 MHz would most likely be:
- CORRECT ANSWER - A duplex Public Correspondence Coast Radio Station frequency.
Which of the following factors does not normally affect the range of VHF transmissions? -
CORRECT ANSWER - Ionospheric refraction.
What is the primary frequency range for terrestrial communications using skywave propagation?
- CORRECT ANSWER - 3-30 MHz
Why is an antenna tuner required for MF-HF transmissions? - CORRECT ANSWER - The
length of physically-fixed antenna must be electrically matched to the intended frequency of
operation.
Midterm (Cal Maritime) UPDATED
ACTUAL Exam Questions and CORRECT
Answers
How many sidebands are present in the J3E mode? - CORRECT ANSWER - One upper
sideband.
A vertical quarter wave antenna with a good ground connection will: - CORRECT
ANSWER - Radiate omni-directionally.
Communications with an emission of F1B/J2B would typically have a channel spacing of: -
CORRECT ANSWER - 0.5 kHz
Which emission mode occupies the most bandwidth? - CORRECT ANSWER - F3E
Which statement best describes amplitude modulation? - CORRECT ANSWER - The
amplitudes in the sideband(s) changes but the radio carrier frequency remains constant.
What is the purpose or function of the antenna coupler? - CORRECT ANSWER -A
Electrically matching the antenna system to the transmit frequency.
B. Changing the overall wavelength of the antenna system (in addition to the fixed length whip.)
C. Enabling maximum transmitted signal on the band chosen by the operator.
For RF communications, "bandwidth" is best defined as: - CORRECT ANSWER - The
portion of the radio spectrum consumed by a particular emission selection and modulation
technique.
A ship has been communicating effectively on 16 MHz during daylight hours with a shore
station at a distance of 3500 miles. Toward late afternoon and evening what effect would be
, noticed? - CORRECT ANSWER - Communications should gradually deteriorate and
become impossible on this frequency at night.
What is the frequency range for Super High Frequency? - CORRECT ANSWER - 3-30
GHz
(3000000kHz-300000000kHz)
What would be the most appropriate HF bands for communicating from San Francisco to Taiwan
or the Philippines? - CORRECT ANSWER - 16 or 22 MHz when daylight at each end and
8 MHz when dark at each end.
What statement best describes modulation? - CORRECT ANSWER - Imposing
intelligence onto a radio carrier signal.
At mid-night, what would be the best choice in attempting to communicate, using SITOR
(NBDP) with a shore station some 800 miles distant? - CORRECT ANSWER - HF bands
A VHF frequency channel pair of TX 157.200 MHz and RX 161.800 MHz would most likely be:
- CORRECT ANSWER - A duplex Public Correspondence Coast Radio Station frequency.
Which of the following factors does not normally affect the range of VHF transmissions? -
CORRECT ANSWER - Ionospheric refraction.
What is the primary frequency range for terrestrial communications using skywave propagation?
- CORRECT ANSWER - 3-30 MHz
Why is an antenna tuner required for MF-HF transmissions? - CORRECT ANSWER - The
length of physically-fixed antenna must be electrically matched to the intended frequency of
operation.
