RYA SRC VHF Channel Usage 3 — Questions and Answers
Question 1: What is the transmission power for most ship-to-shore communications?
- High power (25 watts) for long range communications (Correct answer)
- Low power (1 watt) always
- Maximum power regardless of distance
- Only as much power as the hand-held allows
Correct answer: High power (25 watts) for long range communications
High power (25 watts) should be used for ship-to-shore communications to ensure reliable contact. Low power (1 watt) is used for short-range communications to reduce interference with distant stations.
Question 2: What is the typical VHF radio range at sea?
- 20-30 miles depending on antenna height (Correct answer)
- 5 miles only
- 100 miles or more
- Unlimited with the right equipment
Correct answer: 20-30 miles depending on antenna height
VHF radio has line-of-sight range typically 20-30 miles between vessels and up to 40 miles to shore stations on high ground. Antenna height significantly affects range as VHF cannot propagate beyond the horizon.
Question 3: Which power setting should be used for close-range marina communications?
- Low power (1 watt) (Correct answer)
- High power (25 watts)
- Medium power (10 watts)
- Maximum available power
Correct answer: Low power (1 watt)
Low power (1 watt) should be used for short-range communications such as marina approaches to reduce interference with other stations using the same channel at greater distances.
Question 4: What is a 'working channel' in VHF radio procedure?
- Any channel other than Channel 16 used for the main body of communication (Correct answer)
- Channel 16 used during distress situations
- Channel 70 used for DSC calls
- The channel preset on the radio at the factory
Correct answer: Any channel other than Channel 16 used for the main body of communication
A working channel is any agreed VHF channel (other than the calling/distress channels) on which the substantive communication takes place after initial contact has been made on Channel 16 or via DSC.
Question 5: Can Channel 16 be used for routine ship-to-ship conversation?
- No, it must only be used for distress, safety, calling, and essential navigation (Correct answer)
- Yes, if no other channel is available
- Yes, for short conversations only
- Yes, with permission from HM Coastguard
Correct answer: No, it must only be used for distress, safety, calling, and essential navigation
Channel 16 must not be used for routine conversation. Its sole purpose is distress and safety traffic, calling (to establish contact), and essential navigational communications. All other traffic must move to a working channel.
Question 6: What channel do UK Coast Guard stations primarily broadcast Maritime Safety Information on?
- Channel 16 announcement then Channel 67 or 62 for the broadcast (Correct answer)
- Channel 16 only
- Channel 70 only
- Channel 80
Correct answer: Channel 16 announcement then Channel 67 or 62 for the broadcast
HM Coastguard announces Maritime Safety Information (MSI) broadcasts on Channel 16 and instructs vessels to switch to Channel 67 (or sometimes 62) for the actual broadcast to keep Channel 16 free.
RYA SRC VHF Channel Usage 3
What is the transmission power for most ship-to-shore communications?