‘ BOPP TPF TTDI IHF A DDI IID HHI HEED ASS ne Te ete cet oo alld NOt OO Bt wom PART Ill, CHAPTER 8 WING but was removed after that Operation. When it was determined that the USNS AINSWORTH would again be used for Operation HARDTACK,TG 7.1 requested communications services be provided to support the evacuations of Bikini Atoll. After the equipment was reinstalled, it was requested that it remain installed for possible future use. H&N maintained the radio equipment aboard and operated thetelephone exchange. Personnel required to man the TG 7.5 Com Center during evacuations were assigned from the Nan Com Center. INTER-ATOLL SERVICE 8.9 A 12-channel tropospheric scatter radio system was developed during REDWING to provide inter-atoll communications services. Requirements for HARDTACKgreatly exceeded those for REDWING,and action was taken to obtain a system with suitable band width to accommodate the added requirements. A 72channel tropospheric scatter system, located within a U.S. Air Force Base and d¢termined to be excess to needs, was loaned to the EPG indefinitely. This system was moved from Stewart AFB, New York, and installed at EPG. Sixteen channels were utilized to provide private line subscriber-to-subscriber type service. A 24-channels of encrypted voice (ciphony) service and two channels of teletype service. Also, a channel was allocated to TG 7.1 for use in passing Bikini voice “count-down” to selected Site Elmer subscribers, and a channel was allocated to TG 7.4 for the coordination of air traffic between the Eniwetok and Bikini contro] towers. 8.10 <A total of 51 voice equivalent channels was utilized during Operation HARDTACK. The subscriber-to-subscriber-type private-line channels were eliminated. However, the Bikini Atoll dial system, the additional 2-way dial tie-lines between Eniwetok and Bikini Atolls, and the improvements in ciphony equipment to permit good quality voice service within the designed 50-kc band width (12-channel equivalent) will ensure an adequate number of channels for future operations. SHIP-SHORE SERVICE 8.11 The AN/TRC-24-type radio equipment obtained on loan from military sources was installed at Sites Nan and Elmer to provide radiotelephone and radioteletype service to the USS BOXER and the USNS AINSWORTH. This equipment was also utilized to extend ciphonyservice to the USS BOXER.Radiotelephone channels were connected to Sites Elmer and Nan switchboards, and adequate service was obtained. The increased power of this type transmitter and the use of higher gain directional antenna ashore improved coverage and extended reliable service from as far as 40 to 45 miles from Site Nan. 8.12 A high frequency circuit utilizing frequencies and equipment formerly allocated to inter-atoll service was activated to provide a ship-shore service with the MV and to provide communications with H&N forces engaged in constructingoff-atoll Weather and Rad- Safe Stations. Voice service was considered margina) and procurement action has been initiated to obtain single side-band-type transmitters and receivers to improve voice quality, thereby reducing the volume of CW message traffic. COM CENTER AND CRYPTOGRAPHIC SERVICES 8.13 TG 7.5 provided and operated Com Centers on Sites Elmer, Nan, How, and during evacuation periods, aboard the USNS AINSWORTH. The Com Center on Site How was deactivated when ABMA facilities were re- located to Johnston Island. The principal Com Center was located in Building 208, Site Elmer, and was equipped with on-line crypto circuits to Los Alamos, and to the Sites Nan and Fred crypto. In addition, circuits capable of handling unclassified messages and messages encrypted in off-line crypto systems were installed, connecting the Site Elmer Com Center to Weather Central, Fred relay, and the back-up circuit to the USS BOXER. The average instation handling time for message of all precedences was considerably higher than during the REDWING Operation. This was due to a 33% increase in traffic with no increase in opera- ting work space. Crowded conditions led to lower operating efficiency and an increased numberof security violations. The space situation became so acute that it was necessary to establish a Com Center Annex in the TG 7.1 teleconference facility. This allowed more space for operators to handle the traffic load, but it was not the solution to the space problem. Separating the Com Center function increased supervision problems and the opportunities for committing security violations since it entailed carrying i- fied messages to and from the Annex. Action is being taken to construct an addition to Com- munications Building 224 to accommodate a TG 7.5 Com Center facility. 8.14 TG 7.5 was delegated installation and operating supervision for the Com Center created to process news agency traffic resulting from the PINON event. Theinstallation was made in Building 224, with 8 teletypes machines and 1 facsimile machine to handle the traffic origi- nated by news media representatives. The circuits were connected through military transmitting facilities from Eniwetok to Hawaii and were terminated in Honolulu commercial services. After the PINON shot was cancelled, equipment pas removed and operating personnel were re- eased. Page 57