Should I use a VHF or UHF radio on my boat?
I am outfitting a 40-foot cruiser and looking at handheld radios for the crew to communicate while docking, plus a main unit for the helm. Should I be buying VHF or UHF radios? The UHF ones seem cheaper, but I want to make sure we are legally covered and safe.
Answer
VHF is the global legal standard for marine communication, meaning you must use a marine VHF radio to contact the Coastguard, marinas and other vessels. UHF is invisible to the maritime world and serves only as a short-range tool for crew communication aboard the same boat.
Marine VHF is mandatory
Marine VHF operates between 156 and 174 MHz. It is the only system monitored by HM Coastguard on Channel 16 and UK marinas on Channel 80. A modern fixed VHF radio features Digital Selective Calling (DSC). This allows you to transmit your exact GPS location to rescue services at the push of a red button. UHF lacks this capability.
Fit a fixed 25-watt VHF radio at the helm. Connect it to a masthead or arch-mounted antenna to maximise your line-of-sight range. Quality fixed units like the Icom IC-M330GE or Standard Horizon GX1400G cost between £200 and £250. If your antenna cable run exceeds 10 metres, use thicker RG213 coaxial cable instead of the standard RG58 to prevent signal loss. A waterproof 6-watt handheld VHF serves as the standard backup for crew on deck. The Icom IC-M25 costs around £130. Do not touch a VHF antenna while the radio is transmitting. The 25-watt RF output can cause radio frequency burns.
UHF for internal crew communication
UHF (Ultra High Frequency, 400 to 512 MHz) uses shorter wavelengths. These penetrate steel bulkheads, fibreglass decks and engine room insulation. Large yachts and commercial vessels rely on UHF for internal crew communications.
A typical leisure boat uses licence-free PMR446 UHF radios. These are the standard twin-pack walkie-talkies found in electronics shops. They allow the person on the bow to talk to the helm during anchoring, docking or picking up a mooring. This keeps your conversation private from every boat in a five-mile radius. A set of splash-proof Motorola T82 or Kenwood ProTalk radios costs £60 to £120. Look for an IP67 waterproof rating so they survive being dropped in a puddle on deck.
Range and signal behaviour
VHF signals travel further over open water when the antenna is high up. A 25W fixed VHF with an antenna at the top of a 15-metre mast provides a 20-mile range to another vessel. It reaches up to 30 miles to a tall Coastguard aerial. Handheld VHF radios are limited to 5W or 6W. With a rubber-duck antenna at head height, they reach 3 to 5 miles.