47 CFR §80.753

1. (a)The requirements for reception by a marine VHF shipboard receiver are satisfied if the field strength from the coast station, calculated in accordance with § 80.771 is at least + 17 dBu above one microvolt.
2. (b)These field strengths, voltages and powers at the receiver input are equivalent:
   1. (1)−132 dBW (decibels referred to 1 watt).
   2. (2)1.8 microvolts across 50 ohms.
   3. (3)+ 17 dBu (decibels referred to 1 microvolt per meter).
   4. (4)7 microvolts per meter.