GMDSS. FCC Test 50 – Online Maritime Tests

How are high seas (HF) radiotelephone communications initially established between a vessel and a public correspondence station?

Public Correspondence Stations operate NBDP only.
The vessel calls and establishes voice contact with the public correspondence station on a channel that the station is known to monitor, and the two stations then proceed with their business.
The vessel calls the public correspondence station on VHF Channel 16 and the two stations then switch to the working channel.
The vessel listens for 'free signals' and calls the public correspondence station on the NBDP calling channel with the strongest marker signal.

For RF communications, 'modulation' is best defined as:

Setting up the transceiver with the correct bandwidth to ensure proper communications.
Using a single carrier frequency with the proper power level.
The combination of the received frequency and oscillator frequency in the mixer.
The combination of information or intelligence with a carrier frequency.

For RF communications, 'bandwidth' is best defined as:

The portion of the radio spectrum reserved for frequency allocations by the ITU.
The emission designation resulting from the desired modulation technique.
The portion of the radio spectrum consumed by a particular emission selection and modulation technique.
The modulation technique required to insure proper ITU channel spacing.

When placing a SSB MF/HF call to a Coast Station, you should always:

In an AM signal using voice:

There is a constant amplitude carrier with complex upper and lower sidebands varying in amplitude and frequency.
Varying the amplitude of the carrier and employing both sidebands and the carrier.
Varying only the amplitude of the carrier, depending on Double or Single-Sideband operations.
Varying the amplitude of the carrier and employing both sidebands without the carrier.

The proper sequence of emissions corresponding to the sequence AM-Voice DSB, SSB-Voice without carrier, USB-Voice with carrier and FM-Voice, is:

In FM communications, the information is applied to the carrier by:

Varying only the frequency of the carrier, depending on Double or Single-Sideband operations.
Varying the frequency of the carrier.
Varying the amplitude of the carrier.
Varying the amplitude or the frequency of the carrier, depending on Double or Single-Sideband operations.

The proper sequence of emissions corresponding to the sequence SSB-Voice without carrier, USB-Voice with carrier, FM-Voice and Sitor telex is:

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