October 24, 2016

The Kon-Tiki Expedition and the Heroes of Telemark

Last edited: 08.11.2018

I don't know exactly when I became fascinated by the Norwegian ethnologist, adventurer, and explorer Thor Heyerdahl (1914-2002) and his exciting expeditions, but I guess it must have been at a very young age. I do know that my visit to the Kon-Tiki Museum as a young teenager in the capital of Norway left a deep impression that's still present today more than three decades later. Heyerdahl, his expeditions, and his crew always have been closely tied to ham radio, as this blog entry will show you.

In 1947, Heyerdahl and five companions set out on a balsa wood raft for a journey of almost 7000 km across the Pacific Ocean from Peru to Polynesia. The primitive, hand-built raft was called Kon-Tiki, after the old name of the Inca sun god, and with the voyage Heyerdahl wanted to prove his theory that the Polynesian islands in pre-Columbian times could have been settled or visited by people sailing from South America (contrary to popular believe that it was people from Asia that had settled ancient Polynesia). Heyerdahl had studied the people of South America and Polynesia and believed there was a link between the two.

The Kon-Tiki raft was constructed using only native materials and technologies available to the people of South America in ancient times (no metal was used for instance). It was built copying the indegenous style as recorded in Inca legends and historical accounts of the Spanish conquistadores. The balsa trees, of which, due to massive export of balsa wood, in modern times there weren't many left at the coastal areas, were collected by Heyerdahl personally from inland Equador, to provide for the balsa logs to build the raft on location in Callao, Peru. On the deck of the raft a little hut would be built from bamboo, housing among other things the expedition's radio station.

The Kon-Tiki raft (source)
During the voyage, the men of the Kon-Tiki expedition relied heavily on amateur radio and amateur radio operators to stay in contact with the outside world, and to have their messages relayed to the Norwegian embassy in the US, to the US Weather Bureau, and to the newspapers for instance. The callsign of the amateur radio station carried by the expedition was LI2B.

QSL card of LI2B (source)
The radiomen of the Kon-Tiki expedition were Norwegians Knut Haugland (1917-2009) and Torstein Raaby (1918-1964). Both men were experienced radio veterans and had been radio operator in the Norwegian resistance during World War II. Haugland was decorated by the British for his involvement in underground sabotage actions undertaken to prevent Nazi Germany from producing heavy water (which could have been used to build an atomic bomb) at a plant in Telemark, Norway. The heroic story of the sabotage of the heavy water plant and the transportation of heavy water is nicely told in the 1965 movie The Heroes of Telemark. The film, based on the memoirs of Norwegian resistance soldier Knut Haukelid, was shot on location in Norway and stars actor Kirk Douglas.

The main HF transmitters used on the Kon-Tiki, one for the 40 and 20m band, and one for the 10 meter band, had an approximate RF power output of only 7 Watts. The receiver used was a National Radio Company NC-173. As I understand from an article in the December 1947 issue of QST, the main transmitters also were designed and constructed at the National Company. The equipment was powered by batteries and a hand-cranked generator. They used a wire antenna which was hoisted by a balloon. A special powder and device was used which when coming into contact with sea water would produce hydrogen gas to fill the balloon with. One day however, parrot Lorita, that had come aboard with the expedition, decided to bite through the antenna wire and the balloon was lost. I'm not sure what was used to hoist the antenna afterwards, whether another balloon was available or not, but I've also read stories in which a kite and the raft's mast are mentioned as antenna supports.

National Company Inc. advertisment (source)
National Company, Inc. advertisement (source)
The Academy Award-winning documentary film about the Kon-Tiki expedition released in 1950 contains several scenes featuring the ham radio station and radio communications during the expedition. A compilation can be seen in the YouTube video 7 Watt QRP Ham radio on the Kon-Tiki raft 1947. With the 7 Watts of power they managed to make contact with a radio amateur in Norway, 16,000 km away, which was a sort of world record in itself. At other times they relied mostly on schedules with a network, that had grown as the journey progressed, of radio amateurs mainly in the US.

Experts had predicted that the balsa wood raft would get waterlogged and would sink before it could cross the Pacific, but after a journey of 101 days the Kon-Tiki expedition washed ashore on an uninhabited islet off Raroia atoll, French Polynesia, and Heyerdahl had proved the sceptics wrong. Until the violent landing at the reef of Raroia, throughout the trip the raft had suffered no real damage.

The NC-173 and the transmitters got soaked in the shipwreck, but once on dry land, and after it had dried out in the tropical sun, the receiver gradually started working again. The main transmitter was still not functioning though, and a back-up transmitter (a British Mark II "spy set" from World War II) that they finally managed to get working was used to send an "all well, all well" message from the South Sea islet to their ham contacts. Just in time, as a rescue operation would be launched if nothing would be heard from the expedition in a 36 hour time period after their last message, sent out to radio ham ZK1AB on Rarotonga when the fragile raft had just been smashed on the reef of Raroia, when dry land had still to be reached, and the men's safety was still at stake.

An article called Kon-Tiki Communications - Well Done! appeared in the 1947 December issue of QST, and called the trip the “most unusual expedition ever to place reliance on Amateur Radio for communication". I would like to add this particular QST issue to my collection, and I call upon readers to please let me know when they see it for sale somewhere. A copy of the 1947 December issue of QST in pdf-format can be found here. If you want to learn more about the ham operations of the Kon-Tiki expedition I recommend reading this article, as well as the two articles on the ARRL website of which the links are listed below.

In 2017 it will be 70 years ago that Thor Heyerdahl and his men set out on the adventurous Kon-Tiki expedition. I hope Norwegian hams will not let this go by unnoticed, and will put a couple of Special Event Stations or some special calls on the air.

The Kon-Tiki crew. In the middle Thor Heyerdahl. First from the left: radioman Knut Haugland. Second from the right: radioman Torstein Raaby. (source)

Some sources mention that Knut Haugland was also a licenced radio amateur when not on expedition, holding his own individual callsign, but I haven't been able to confirm this. Haugland is reported to have been holding the call LA3KY, but that's most probably not correct.

Interesting tidbit here is that the radio amateurs working at the meteorological station and the LORAN station on the remote Arctic island of Jan Mayen, for amateur radio operations have a special hut to their disposal called Tikkebu. "Bu" means something like "small hut" in Norwegian. It was originally called "Kontikibu" because the first commander of the LORAN station had been radio operator at the Kon-Tiki expedition. This most probably was Torstein Raaby. If this means that Raaby was also active from Jan Mayen as a radio amateur, I do not know.  Fact is that prior to 1947 Haugland and Raaby had no previous ham radio experience.

"Tikkebu" on Jan Mayen island at 71º northern latitude (source)
The callsign LI2B was used by Heyerdahl again in 1969-70 on the Ra expeditions with a papyrus reed boat sailing from Morocco to Barbados.

DVD's from the collection of PA7MDJ, and recommended viewing when you're interested in the radio operations of the Kon-Tiki expedition and the sabotage of the Heavy Water plant in Telemark during WWII. From left to right the 1950 documentary film about the Kon-Tiki expedition, the 1965 movie "The Heroes of Telemark", and the 2012 Norwegian dramatised feature film "Kon-Tiki".

Addendum 08.11.2018
In the book A Hero for the Atomic Age: Thor Heyerdahl and the Kon-Tiki Expedition (Axel Andersson, 2010) the radio related part of the Kon-Tiki Expedition is given a lot of attention to starting at page 45. I do not own the book myself, but pages 45, 46, and 47 can be read in the online example at Google Books here.

A nice article by Kris Partridge G8AUU on the Kon-Tiki Expedition and its radio operations appeared on the SWLing Post site here. The article even mentions the blog post by yours truly, for which many thanks!

Paul ZS2OE provided some very interesting additional info on the radio operations of the Kon-Tiki expedition. You can read it in the comments of this blog post. Many thanks for that Paul!

See also:


  1. Very nice piece Michael. Like you I have been fascinated with the expedition since I was a youngster, after having read the book at school and I still have the copy. I have always wanted to sail the original route from Callao to Polynesia...just need to decide to do it one day. Something that may interest you regrading the antenna used on the raft: the design in daily use was an inverted L which was strung from the mast and run to the rear of the raft. The balloon antenna was an experiment which did not work out too well due to the heat of the sun ! The one major thing in their favour was the solar cycle which peaked very high that year and helped greatly to get their low power 20m signal out. I put my interest in QRP down to the expedition and I never use more than 5 watts here. 73 from South Africa ! de Paul ZS2OE

    1. Thank you very much for your nice comment and for the very interesting additional info, Paul! Thanks for reading my blog! Best 73 and good QRPing de PA7MDJ