FCC MROP cheat sheet

47 CFR Part 80 contains the FCC rules for the maritime radio services; the Marine Radio Operator Permit (MROP) authorizes radiotelephone operation on vessels that are required to carry a radio.

An MROP is issued for the lifetime of the holder and does not expire; a GMDSS Radio Operator License or a higher class license also satisfies the operator requirement.

A ship station license is required for a vessel that carries a marine radio transmitter, is issued by the FCC for a ten-year term, and assigns the vessel's call sign.

VHF Channel 16 (156.800 MHz) is the international distress, safety, and calling frequency; Channel 9 (156.450 MHz) is the secondary calling channel used by recreational vessels.

Channel 13 (156.650 MHz) is the bridge-to-bridge navigation channel and is limited to 1 watt output except when higher power is required for safety.

Stations must identify with the call sign or vessel name at the beginning and end of each exchange and at least every 15 minutes during a long transmission.

False or fraudulent distress signals, obscene or profane language, advertisements, and superfluous transmissions are prohibited and subject to monetary forfeitures and license revocation.

A 406 MHz EPIRB is registered with NOAA, not the FCC, and the registration must be updated whenever the vessel, owner, or emergency contacts change.

MAYDAY, spoken three times on Channel 16 or 2182 kHz, announces grave and imminent danger and a request for immediate assistance.

PAN-PAN, spoken three times, announces an urgent situation concerning the safety of a vessel or person that does not yet involve immediate danger of loss of life.

SÉCURITÉ, spoken three times, precedes an important safety message such as a navigational or weather warning; traffic then shifts to a working channel.

Distress call order: MAYDAY (x3), THIS IS, vessel name and call sign (x3), MAYDAY, name, position, nature of distress, type of assistance required, number of persons aboard, and other useful information.

MAYDAY RELAY precedes a distress message retransmitted on behalf of a station that cannot itself transmit a distress call.

Distress traffic has absolute priority; SEELONCE MAYDAY imposes radio silence on the frequency, SEELONCE FEENEE lifts it, and PRU-DONCE marks urgency or safety silence.

Channel 70 (156.525 MHz) is reserved for Digital Selective Calling only; a DSC distress alert is followed by a voice MAYDAY on Channel 16.

A false distress alert must be cancelled by sending MAYDAY, ALL STATIONS (x3), THIS IS, vessel name, and a statement that the distress alert is cancelled.

A station should acknowledge a distress message only when it can render assistance or when no other station has acknowledged; otherwise it stands by and keeps silence.

A radio log is required on vessels required to carry radio; entries include date and time in UTC, frequencies used, stations contacted, and all distress, urgency, and safety traffic.

Logs must be retained for at least one year and made available for inspection by FCC or U.S. Coast Guard representatives.

Prowords: ROGER means received; WILCO means received and will be complied with; OVER invites a reply; OUT ends the exchange, and 'over and out' is never used.

Phonetic alphabet: ALFA, BRAVO, CHARLIE, DELTA, ECHO, FOXTROT, GOLF, HOTEL, INDIA, JULIETT, KILO, LIMA, MIKE, NOVEMBER, OSCAR, PAPA, QUEBEC, ROMEO, SIERRA, TANGO, UNIFORM, VICTOR, WHISKEY, X-RAY, YANKEE, ZULU.

Numbers are transmitted digit by digit, preceded by the word 'figures' when ambiguity is possible; a word to be spelled is preceded by 'I spell'.

Routine radio checks are made on Channel 9 or a working channel at low power, never on Channel 16 and never on Channel 70.

Time is stated on the 24-hour clock; UTC (Zulu) is standard, and local time is used only when the zone is clearly identified in the log.

Channel 6 is the primary intership ship-to-ship channel; Channels 68, 69, 71, 72, and 78A are non-commercial working channels.

A listening watch on Channel 16 is maintained while underway unless the radio is engaged on another authorized channel or a DSC watch is being kept.

Wavelength in meters = 300 ÷ frequency in MHz; Channel 16 at 156.800 MHz has a wavelength of about 1.9 m, so a quarter-wave whip is about 0.48 m long.

Marine VHF uses frequency modulation with vertical polarization and 25 kHz channel spacing; duplex channels separate ship transmit (156–157 MHz) from coast transmit (161–162 MHz) by 4.6 MHz.

Maximum authorized power for a fixed marine VHF station is 25 watts; Channels 13, 6, 72, and 77 are limited to 1 watt.

Ohm's law: E = I × R, and power P = E × I = I²R = E²/R.

Marine VHF coaxial feedline has a 50-ohm characteristic impedance, PL-259 connectors are standard, and low-loss cable reduces power lost between transmitter and antenna.

A VSWR of 1:1 is a perfect match; a reading above 2:1 indicates an antenna or feedline fault that reflects power and can overheat the transmitter.

VHF propagation is essentially line-of-sight; usable range in nautical miles is roughly 1.23 × the square root of antenna height in feet.

A 406 MHz EPIRB transmits to the COSPAS-SARSAT satellite system and carries a 121.5 MHz homing signal; a SART responds to 9 GHz (X-band) radar.