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WWII-era Radio Comms

     Naval radio communication played a vital role in World War II efforts and in Hawai'i’s defensive installation. The wireless radio was invented by Marconi in the late nineteenth century and the Navy was quick to make use of the new technology. The basic wireless invention went through a rapid evolution between the first and second World Wars. By 1940, the Naval communication system included technology capable of high, medium, and low frequencies that could send signals out to all corners of the globe (U.S. Dept. Navy, 1947:401).

    In Hawai'i, Navy communications began in September, 1916, at Hospital Point, Pearl Harbor. In 1920 a receiver station was constructed at Wailupe. At the time it was considered one of the largest radio receivers in the world and could receive six messages simultaneously. In 1931 land was bought in Lualualei Valley for the purpose of constructing a new transmitter facility. In 1936 the Lualualei Valley transmitter was activated (HABS, 1997:6).

     With the outbreak of World War II, radio communication stations in Hawai'i were built as rapidly as all other military operations that combined to make the Pacific offensive. The result was an overseas radio facility program that was advanced in proportion and technology above other area installations. The Army had three major and several minor radio installations. The Navy’s radio station installations grew rapidly. Along with the previously erected Naval station at Lualualei Valley was a naval communications station at Wahiawa, near Schofield Barracks. The station was commissioned on December 21, 1941, and grew to be one of the largest Naval radio stations in the world at that time (Allen, 1950: 226).

     However, the Naval fleet expansion into the Pacific created communication needs that were not yet being met. The Submarine Base at Pearl Harbor, established in 1919, found itself at the forefront of war operations for the Pacific during World War II. As the submarines left the harbor and ventured into Japanese waters there was an exigency for communication (Allen, 1950: 225).

  One more item was needed to give the Pacific fleet full striking power: absolute certain means of radio communications with headquarters at Pearl. The new receiving station at Wahiawa amply met these requirements but the main Navy transmitter at Lualualei was not powerful enough for an all-ocean war. A giant sending station must be built that would reach not only to the waters of Australia and the Indian Ocean but also to every Allied submarine-submerged-especially if she were on the bottom of Tokyo harbor (Woodbury, 1946:349).


     It was deemed that the 600 foot tower at Lualualei was not powerful enough to send radio waves of the length necessary for communication in the Pacific. A system was needed that could send messages to the bottom of Tokyo harbor. The initial problem was how to build a tower higher than 600 feet. The Navy believed it possible to use the natural geography to create the necessary height. In Java there had been successful experimentation by the Dutch of such a facility using cables strung between two mountain peaks (Woodbury, 1946: 350).


     The Navy quickly decided to build a long range low frequency radio station in Hawai'i using this type of natural resource. The station was highly experimental and also highly classified. The station would be able to obtain long range signals because it would use a very low frequency. The huge, high powered antennas would send out stable, long waves that were able to travel long distances and penetrate intrusions, such as mountains and water. The system would also require a transmitter building at the bottom of the valley, placement of anchors at the ridge of the cliffs, wires running from the anchors to the transmitter, and a copper grid system in the valley to assist in conducting the signals.

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Upper hoist house view from the peak of Pu'u Keahiakahoe


Lualualei Naval Radio Transmitting Facility. The main antennas were completed in 1935 and the facility was activated in 1936

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Interior view of antenna trunk opening and entry door
Images courtesy of

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Sept 1945 base map of the Tokyo Bay Area from the Digital Collections of the National WWII Museum

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Cables were winched into place using the winches housed in the upper hoist house, pictured above, with Kāne'ohe in the background

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There were 56 valves in the pump room for the diesel-powered alternator 

Antennae across Ha'ikū Valley

Antennae across Ha'ikū Valley looking out to Kāne'ohe Bay

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The control panel for the Alexanderson Alternator housed in the Naval Radio Station

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The transmitter room in the Naval Radio Station

Mahalo nui to Dave Jessup, Ted Urquhart, John Flanigan, and others for the historic images and information on this page
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