GMDSS. FCC Test 53

The purpose of 'parity' in SITOR communications is?

Error correction in ARQ communications.
All of the above are true.
Error correction in NAVTEX broadcasts.
Error correction in FEC weather and navigational broadcasts.

What is the best method for a GMDSS Radio Operator to determine which SITOR station to contact for the purpose of sending a chargeable message or cable?

Listen to each station's voice announcement and determine which channel(s) will be monitored.
Listen to each station's free signals, and call the station generating the loudest free signal marker.
Listen to the U.S. Coast Guard's traffic list to determine which Coast Guard station will handle commercial traffic.
Listen to each station's MSI broadcast to determine which public correspondence station to contact.

Which of the following would be a valid selcall for use in ARQ communications?

212420 WHAQ X.
Four marks (ones) and three spaces (zeroes) forming the binary signal "1001101".
This is established by the communications protocol used with the modem.
1106

Which of the following methods will give a GMDSS Radio Operator the best indication of whether ARQ communication can be established with a coast radio station?

Monitor the coast radio station's 'free signals' and call on the frequency on which the loudest and most consistent signals are heard.
Selecting a frequency in the MF band averts interference from severe static discharges.
Referring to propagation charts will tell the Operator when the eruption of communication shattering solar flares will occur.
Re-position the radome's antenna toward the coast radio station and press the 'call request' button.

During Sitor ARQ operations through a coast station, what should the GMDSS operator do during the 'Automatic Exchange of Answerbacks.'

Do nothing other than wait for a GA+ prompt.
Send the necessary message file and then wait for time and charges.
None of the above.
Send a 'WRU' then a 'Here is' when requested by the coast station.

'SITOR' communications are based on a digital code system:

Consisting of 5 bits telex and 8 bits Fax.
Consisting of 7 bits, with four ones and three zeros.
Consisting of 5 bits for ship stations and 7 bits for shore stations.
Consisting of 7 bits, with four zeros and three ones.

When placing a telex call to a Coast Station, you should always:

Tune the transmitter on another frequency.
Choose the closest station.
Wait until the coast station sends his Traffic List.
Make sure the frequency is not occupied with normal traffic.

Once ARQ communication with the coast radio station has been established, which of the following exchanges will most likely take place?

None of the above.
The vessel then requests the coast radio station's selcall so that communication can be set up on the appropriate working channel.
Since communication has already shifted to the working channel, the vessel then transmits the subscriber number and text of the message to be sent for the coast radio station to store and forward.
After exchanging answerbacks with the vessel, the coast radio station transmits 'GA+'.

After establishing contact with a Coast Station on an available channel, which of the following exchanges take place?

The ship station begins transmitting the text.
The coast station transmits its answerback, asks for the ship's answer back and then transmits GA+.
None of these.
The vessel will request the shore station's answerback to confirm it has reached the correct station, then the shore station operator will request billing authorization.

Which statement is correct regarding HF NBDP under GMDSS?

Safety communications by direct-printing telegraphy should be in the ARQ mode when communicating with the U.S. Coast Guard or other coast stations on channels that they normally guard.
Distress communications other than directly to the Coast Guard or other coast stations on the channels that they normally guard, should be in the broadcast SSB mode.
Distress communications other than directly to the Coast Guard or other coast stations on the channels that they normally guard, should be in the broadcast FEC or SSB mode.
The ARQ mode may be used subsequently to the FEC mode when it is advantageous to do so.

Review Answers

GMDSS. FCC Test 53

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