VHF Radio

What is a marine VHF radio?

The maritime VHF band carries approximately 88 channels worldwide, split into US, international, and inland sub-plans. Channel 16 (156.800 MHz) is the international distress, safety, and calling channel, and any vessel with a VHF radiotelephone must maintain a continuous listening watch on it whenever the set is not in active use. Channel 70 (156.525 MHz) is reserved for Digital Selective Calling and carries no voice traffic.

Two physical formats sit on every yacht. The fixed-mount unit on the bridge transmits at up to 25 W and, with a masthead antenna, reaches 15-25 nautical miles vessel-to-vessel and up to 60 nm to a tall coast tower. Fixed sets are certified as Class A or Class B DSC on SOLAS ships, and Class D DSC on yachts and recreational craft. The handheld VHF is the captain's tender and back-up radio, rated to 5-6 W and Class H DSC, with a practical range of 1-5 nm. Range is line-of-sight, so antenna height matters more than transmit power.

Why it matters for yacht owners

For any commercially coded yacht, and most private yachts above 24 m, the VHF/DSC installation is the regulatory minimum that lets the vessel leave the dock. SOLAS Chapter IV, Regulation 7 mandates a VHF-DSC fit for GMDSS Sea Area A1, and the MCA Large Yacht Code (LY3, now consolidated into the Red Ensign Group Yacht Code Section 16) requires two independent ship-to-shore distress means and a continuous radio watch underway.

The DSC distress button, once a valid MMSI is programmed and a GPS feed wired in, automatically transmits your yacht's identity and position to nearby vessels and coast stations before the captain can reach for a satellite phone. Insurance underwriters, classification societies, and charter contracts all expect a documented, working installation; pre-purchase surveys fail without one. The state of the VHF fit is a quick proxy for how seriously the previous owner treated compliance.

Key facts

• Operates on 156-174 MHz FM in the ITU VHF maritime mobile band.
• Channel 16 is the international distress and calling channel; Channel 70 is reserved for DSC.
• Fixed-mount sets transmit at 25 W with 15-25 nm vessel-to-vessel range; handhelds at 5 W reach 1-5 nm.
• DSC classes: A and B for SOLAS ships, Class D for yachts, Class H for handhelds.
• SOLAS Chapter IV Regulation 7 mandates VHF-DSC for GMDSS Sea Area A1; MCA LY3 / REG-YC Section 16 applies to commercial yachts of 24 m and above.
• DSC requires a programmed MMSI and GPS feed; the distress button is inert without both.