Principles Of Radio Comms Flashcards
What are the three methods of propagation?
- Space (Direct) Wave
- Sky Wave
- Ground (Surface) Wave
What kind of propagation does each of these frequencies use?
- VHF
- MF
- HF
- VHF = Space (Direct) Wave
- MF = Ground (Surface) Wave
- HF = Sky Wave
When can we use a DSC alert and announcement only?
- Alert is Used Only for Distress.
- Announcement is used for urgency, safety and routine.
Difference between designated and undesignated DSC?
- Designated: Specifies the type of Distress
- Undesignated: doesn’t Specify type, only sends Position and MMSI
What are the VFH primary internship channels?
- CH06
- CH08
- CH72
- CH77
What is VHF channel 13 used for?
Ship-to-Ship Safety of Navigation
Which VHF channel would you initiate a DSC distress alert to, and which would you make the RT call and message on?
- DSC Distress Alert on VFH CH70
- RT Call and Message on VHF CH16
What is 2189.5 kHz frequency used for?
Ship-to-Shore Routine Calling
What is 2177 kHz frequency used for?
Ship-to-Ship & Ship-to-Shore Routine Calling
What is 2048 kHz frequency used for?
Internship Routine Working
Which MF frequencies would you initiate a DSC distress alert to, and which would you make the RT call and message on? And which is for Telex?
- DSC Distress Alert = 2187.5 kHz
- Distress Call & Message = 2182 kHz
- Telex = 2174.5 kHz
What are the bands of frequency for HF?
- 2 (MF)
- 4
- 6
- 8
- 12
- 16
Which type of antenna does a VHF use?
Half-Wave Dipole Antenna
Which type of antenna does the MF/HF use?
Whip Antenna w/Antenna Tuning Unit (ATU)
Which type of antenna does Inmarsat-C use?
Omni-Directional
Which type of antenna does Inmarsat-B use?
Dish Antenna w/Gyro-Stabilized Platform
How long after for initial DSC call to be repeated? And then for how long after the second attempt)
5 minutes, and then at least 15 minutes
