Kon Tiki's transmitters were powered by batteries and a hand-cranked generator and operated on the 40, 20, 10, and 6-meter bands. Each unit was water resistant, used 2E30 vacuum tubes, and provided approximately 6 watts of RF output; the equivalent of a small flashlight. Two British 3-16 MHz Mark II transmitters were also carried on board, as was a VHF transmitter for communicating with aircraft and a hand-cranked Survival radio of the Gibson Girl type for 500 and 8280 kHz.
The radio receiver used throughout the voyage, a National Radio Company NC-173, once required a thorough drying out after being soaked when landing in Raratonga. The crew once used a hand-cranked emergency transmitter to send out an "all well, all well" message "just in time to head off a massive rescue attempt".
The call sign LI2B was used by Heyerdahl again in 1969–70, when he built a papyrus reed raft and sailed from Morocco to Barbados in an attempt to show a possible link between the civilization of ancient Egypt and the New World.