Station , also known as Fleet Radio Unit Pacific () was the United States Navy signals monitoring and cryptographic intelligence unit in Hawaii during World War II. It was one of two major Allied signals intelligence units, called Fleet Radio Units in the Pacific theaters, along with in Melbourne, Australia. The station took its initial name from the phonetic code at the time for "H" for Heʻeia, Hawaii radio tower. The precise importance and role of in penetrating the Japanese naval codes has been the subject of considerable controversy, reflecting internal tensions amongst US Navy cryptographic stations. was under the control of the OP-20-G Naval Intelligence section in Washington. Before the attack on Pearl Harbor of December 7, 1941, and for some time afterwards, was in the basement of the Old Administration Building at Pearl Harbor. Later on, a new building was constructed for the station, though it had been reorganized and renamed by then. Background Cryptanalytic problems facing the United States in the Pacific prior to World War II were largely those related to Japan. An early decision by OP-20-G in Washington divided responsibilities for them among at Cavite and then Corregidor, in the Philippines, in Hawaii, and OP-20-G itself in Washington. Other Navy crypto stations, including Guam and Bainbridge Island on Puget Sound were tasked and staffed for signals interception and traffic analysis. The US Army's SIS broke into the highest level Japanese diplomatic cypher (called by the US) well before the attack on Pearl Harbor. produced little of military value, as the Japanese Foreign Ministry was thought by the ultra-nationalists to be unreliable. Furthermore, decrypts from , eventually called MAGIC, were poorly distributed and used in Washington. SIS was able to build several machine equivalents. One was sent to , but as 's assigned responsibility did not include traffic, no machine was ever sent there. The absence of such a machine on site in Hawaii has long been seen by conspiracy theorists as a reason for US unpreparedness in Hawaii, and/or to be evidence of a conspiracy by high level officials to deprive Pearl Harbor of intelligence known to Washington. However, no hard evidence for any such conspiracy exists. Japanese naval signals in 1941 and early 1942 was assigned responsibility for work on Japanese Navy systems, and after an agreement with Australia, the United Kingdom and Netherlands to share the effort, worked with crypto groups based at