CHAPTER Ill, SECTION & 159 Prior to the activation of the VHF interatoll system, the communication link between Eniwetok and Bikini Atolls consisted of a twochannel HF system with capabilities of one unsecured voice channel and one on-line crypto teletype channel. During the build-up phase, the telephone channel became overloaded and delays of three to four hours were experienced. However, with the activation of the VHF cir- cuits, satisfactory service was provided. The HF circuit was kept activated as a back-up system in case of VHF system failure. The VHF system (See Chapter II, Section 4,) consisting of 17 circuits for both classified Traffic was generally heaviest just prior to the test events, falling off shortly after. No serious backlogs occurred - the system as installed was adequate in all respects; it was capable of carrying an additional 10 to 20 per cent more traffic on the Elmer-Nan circuit and even greater increases on the other circuits. No major variations from the original planning for message handling were necessary. The Contractor’s personnel, because of Cryptographic Clearance requirements, were not in- volved with the operation of the AFSAY 806 cyphony equipment. However, it was determined that this equipment was not satisfactory for use by scientific personnel. Unscrambled voice signals were badly distorted and a considerable amount of repetition and rephrasing was necessary. Because of this condition, scientific personnel avoided the use of this equipment. Teleconference service between Elmer and Nan was first established in late April. At Elmer this consisted of a special teleconference room; at Nan, conferees assembled outside of the Comcenter and messages were hand-passed. This service proved very satisfactory, and during the first weeks of operation, fourteen conferences were held with an average time of one and one- half hours each. PERPEPEBISE REE Se and unclassified voice teletype communications, wasfirst activated in April 1956. Terminals for this system were located at Elmer and Nan as well as on the USS Curtiss and USNS Ainsworth. An aircraft repeater provided: replacement of the Nan repeater in case of equipment failure; replacement of the Nan repeater during the times when the Curtiss was in transit between atolls and out of range of the Nan repeater but not yet in range of the Elmer facility; and for direct communications between the ships and Elmer. The aircraft repeater was also used to effect line-of-sight communications between the USS Curtiss at Bikini and site Elmer, if ionospheric disturbances disrupted the transmission path. The airborne repeater was tested at the time of the Cherokee and Zuni events, but as there were no interruptions because of ionospheric conditions, this facility was no longer required. aLaie we eng nes a * pene? eo Sw . <p a: oe 7 peere Figure 3-15. &: 7O-/90 . ius <a on Antennas of VHF - Interatoll Communications Eniwetok and Bikini Atolls were each pro- vided with an integrated wire telephone system consisting of a 280-line manual board at Elmer with connecting service to Fred, Yvonne, Ursula and Gene and an 80-line manual board at Nan with connecting service to Fox and Tare. The Fred board was a 400-line dial exchange operated by TG 7.2. This exchange did not have information or assistance operators and all such cails were handled by the Elmer operators at the “Toll” operating position. During the operational phase, the Elmer telephone switchboard was often heavily overtaxed with every available line in service. The telephone operating positions were insufficient to enable operators to keep ahead of incoming calls and completed (disconnect) calls had to be handled by support operators standing behind the regular operators. Page 3-47