scope:

This ETS states the minimum requirements for VHF transmitters and receivers fitted with a 50 Ω external antenna socket or connector for use on board ships and operating in the bands between 156 and 174 MHz allocated to the maritime mobile service by the Radio Regulations 1) (see Radio Regulations, Appendices 18 [1] and 19 [2]). The relevant requirements detailed in the Radio Regulations and the International Maritime Organization Recommendations A.385, A.524, A.569 and A.609 are incorporated.

The VHF maritime mobile service uses both single-frequency and two-frequency channels. For two-frequency channels the Radio Regulations require a separation of 4,6 MHz between the transmitting frequency and the receiving frequency.