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NIOC Yokosuka
Command History

       On 15 December 1945, the first Communications Supplementary Activity Detachment (COMSUPACT Det) was established in Ohminato, Japan. When the Army evacuated the area in April 1946 the detachment was relocated to Yokosuka, and was redesignated as Communications supplementary Activity (COMSUPACT) Yokosuka. On 22 November 1948, NAVCOMMUNIT 35 was established and added a direction finding capability to COMSUPACT Yokosuka. A full rhombic antenna field was constructed in February 1949 to make the HFDF site fully operational. In 1950, Naval Security Group (NAVSECGRU) decided to shift net control of the Pacific HFDF net to Yokosuka from Wahiawa, Hawaii.

     To accommodate this change NAVCOMMUNIT 35 was expanded to 38 officers and 392 enlisted and was located in renovated building F-68. The HFDF net was activated in Yokosuka on 2 October 1950. On 15 January 1960, the Naval Security Department (NSG) was commissioned as the US Naval Security Group Activity (NSGA) Kami Seya. NAVCOMMFAC at Kami Seya was relocated back to Yokosuka as Naval Communications Station (NCS) Yokosuka. On 23 January 1968, the USS PUEBLO (AGER-2) was captured by the North Koreans. At the time of the attack NSGA Kami Seya was in communication with the ship.

     There were six Sailors who were deployed on the USS Pueblo, they returned to NSGA Kami Seya 11 months later. On 1 August 1969, all NAVSECGRU elements at Yokosuka were consolidated under one command structure. Naval Security Group Detachment Yokosuka, Japan, a detachment of NSGA Kami Seya, was established. In March 1971 most of the operational functions were moved from NSGA Kami Seya to NSG Detachment Misawa, Japan. On 30 June 1971, NSGA Kami Seya was downgraded to NSG Detachment Kami Seya and NSG Detachment Misawa was commissioned as NSGA Kami Seya. Activities at Kami Seya and Yokosuka became detachments of NSGA Misawa. On 23 May 1984, NSG Detachment Kami Seya was recommissioned as an NSGA. In January of 1989 NSG Detachment Yokosuka became a detachment of Kami Seya again.

     On 1 June 1995, NSGA Kami Seya was closed permanently and NSG Detachment Yokosuka was recommissioned as an NSGA. On 30 September 2005, Naval Security Group was closed and many NSG Activities were closed as well. Those that remained open were recommissioned as Navy Information Operations Command (NIOC) on 1 October 2005, including NIOC Yokosuka. On 29 January 2010, the US TENTH Fleet was recommissioned for Fleet Cyber Command. NIOC Yokosuka is currently subordinate to TENTH Fleet.
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Last Modified: April 2nd, 2014
Last Reviewed: March 31st, 2014