Login or Register for FREE!
Subelement C
Equipment Operations
Section 18
Equipment Faults
Under normal circumstances, what do you do if the transmitter aboard your ship is operating off-frequency, overmodulating or distorting?
  • Reduce to low power.
  • Reduce audio volume level.
  • Correct Answer
    Stop transmitting.
  • Make a notation in station operating log.

Under normal circumstances, what do you do if the transmitter aboard your ship is operating off-frequency, overmodulating or distorting?

(A). Stop transmitting.

Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart
C - Operating Requirements and Procedures

§ 80.90 Suspension of transmission.

Transmission must be suspended immediately upon detection of a transmitter malfunction and must remain suspended until the malfunction is corrected, except for transmission concerning the immediate safety of life or property, in which case transmission must be suspended as soon as the emergency is terminated.

§ 80.92 Prevention of interference.

47 CFR 80.92(a) The station operator must determine that the frequency is not in use by monitoring the frequency before transmitting, except for transmission of signals of distress.

47 CFR 80.92(b) When a radiocommunication causes interference to a communication which is already in progress, the interfering station must cease transmitting at the request of either party to the existing communication. As between nondistress traffic seeking to commence use of a frequency, the priority is established under § 80.91.

47 CFR 80.92(c) Except in cases of distress, communications between ship stations or between ship and aircraft stations must not interfere with public coast stations.

The ship or aircraft stations which cause interference must stop transmitting or change frequency upon the first request of the affected coast station.

Last edited by markadlerdallas. Register to edit

Tags: none

Which would be an indication of proper operation of a SSB transmitter rated at 60 watt PEP output?
  • In SSB (J3E) voice mode, with the transmitter keyed but without speaking into the microphone, power output is indicated.
  • Correct Answer
    In SITOR communications, the power meter can be seen fluctuating regularly from zero to the 60 watt relative output reading.
  • In SSB (J3E) mode, speaking into the microphone causes power meter to fluctuate slightly around the 60 watt reading.
  • A steady indication of transmitted energy on an RF Power meter with no fluctuations when speaking into the microphone.

Which would be an indication of proper operation of a SSB transmitter rated at 60 watt PEP output?

(B). In SITOR communications, the power meter can be seen fluctuating regularly from zero to the 60 watt relative output reading.

FCC requires that you stay within the prescribed frequency and power limitations. As it is possible to easily cross the legal allocation, it is best to stay close but not reaching the legal limits.

As you talk, the power output indicator should bounce with the fluctuations of your voice, within legal power limits.

Also, if you get a steady power reading, something is wrong, since you are modulating by voice.

SITOR (SImplex Teletype Over Radio) is a system for sending text messages. It was an improvement on the old RTTY radio teletype. This mode has error correction through the use of the automatic repeat request (ARQ). If error noticed, retransmission is requested.

For more info, please see Wikipedia's article on SITOR

Last edited by markadlerdallas. Register to edit

Tags: none

If a ship radio transmitter signal becomes distorted:
  • Reduce transmitter power.
  • Use minimum modulation.
  • Correct Answer
    Cease operations.
  • Reduce audio amplitude.

If a ship radio transmitter signal becomes distorted:

(C). Cease operations.

Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart
C - Operating Requirements and Procedures

§ 80.92 Prevention of interference.

47 CFR 80.92(a) The station operator must determine that the frequency is not in use by monitoring the frequency before transmitting, except for transmission of signals of distress.

47 CFR 80.92(b) When a radiocommunication causes interference to a communication which is already in progress, the interfering station must cease transmitting at the request of either party to the existing communication. As between nondistress traffic seeking to commence use of a frequency, the priority is established under § 80.91.

47 CFR 80.92(c) Except in cases of distress, communications between ship stations or between ship and aircraft stations must not interfere with public coast stations.

The ship or aircraft stations which cause interference must stop transmitting or change frequency upon the first request of the affected coast station.

Last edited by markadlerdallas. Register to edit

Tags: none

What would be an indication of a malfunction on a GMDSS station with a 24 VDC battery system?
  • Correct Answer
    A constant 30 volt reading on the GMDSS console voltmeter.
  • After testing the station on battery power, the ammeter reading indicates a high rate of charge that then declines.
  • After testing the station on battery power, a voltmeter reading of 30 volts for brief period followed by a steady 26 volt reading.
  • None of the above.

What would be an indication of a malfunction on a GMDSS station with a 24 VDC battery system?

(A). A constant 30 volt reading on the GMDSS console voltmeter.

A proper functioning 24 VDC battery system would:

  • After testing the station on battery power, the ammeter reading indicates a high rate of charge that then declines.

  • After testing the station on battery power, a voltmeter reading of 30 volts for brief period followed by a steady 26 volt reading.

A 24 Volt battery system may read 26 Volts or slightly higher for a brief period of time, depending on the state of charge of the batteries. However, a constant reading of 30 volts would indicate some type of malfunction.

For more info, please see West Marine site's article on 24 Volt Electrical Systems

Last edited by markadlerdallas. Register to edit

Tags: none

Your antenna tuner becomes totally inoperative. What would you do to obtain operation on both the 8 MHz and 22 MHz frequency bands?
  • Without an operating antenna tuner, transmission is impossible.
  • It is impossible to obtain operation on 2 different HF bands, without an operating antenna tuner.
  • Bypass the antenna tuner and shorten the whip to 15 ft.
  • Correct Answer
    Bypass the antenna tuner. Use a straight whip or wire antenna approximately 30 ft long.

Your antenna tuner becomes totally inoperative. What would you do to obtain operation on both the 8 MHz and 22 MHz frequency bands?

(D). Bypass the antenna tuner. Use a straight whip or wire antenna approximately 30 ft long.

If the antenna tuner is inoperable, it won't match impedance (in Ohms) between transmitter and the antenna, causing reflected power back to the transmitter, or other malfunctions.

In salt water environment, the whip antenna, or vertical polarization is better is the waves bounce well off the water. But horizontal wire may also work, though not as well.

Antennas may be in 1/4, 1/2, 5/8, 3/4, or full wavelengths.

The 22MHz has a wavelength of approximately 13.6 meters and 8 MHz is approximately 37.5 meters. Radio waves travel close to speed of light, so 300,000 km per second/8,000 kHz, or 300/8=37.5 meters. 300/22=13.6 meters.

Since the answer is in feet, meters have to be converted to feet, and then the right fraction applied.

An antenna of 30 ft is about 1/4 wave on 8 MHz and 3/4 waves on 22 MHz.

For 8 MHz, the 37.5 meters is about 123 feet, so 1/4 is about 30 feet.

For 22 MHz, the 13.6 meters is about 44.6 feet, so 3/4 is about 30 feet.

This 30 feet is the common length for both frequencies.

Last edited by markadlerdallas. Register to edit

Tags: none

Which of the following conditions would be a symptom of malfunction in a 2182 kHz radiotelephone system that must be reported to the Master, then logged appropriately.
  • Much higher noise level observed during daytime operation.
  • Correct Answer
    No indication of power output when speaking into the microphone.
  • When testing a radiotelephone alarm on 2182 kHz into an artificial antenna, the Distress frequency watch receiver becomes unmuted, an improper testing procedure.
  • Failure to contact a shore station 600 nautical miles distant during daytime operation.

Which of the following conditions would be a symptom of malfunction in a 2182 kHz radiotelephone system that must be reported to the Master, then logged appropriately.

(B). No indication of power output when speaking into the microphone.

Power output on an SSB transceiver is directly related to the amount of audio going into a microphone. SSB communication mode suppresses the carrier signal and the LSB, or the lower side band (a mirror of the SSB), and so all the power concentrates in the SSB frequency.

If no output, the radio may be not working at all. The MF frequency of 2182 kHz, selected for distress messages, demands that the malfunction should be reported.

Noise level and failure of contact may be due to propagation, not a radio problem.

Last edited by markadlerdallas. Register to edit

Tags: none

Go to 17 Go to 19