415 INTERATOLL COMMUNICATIONS. At the close of Operation CASTLE, TG 7.1 transferred two high-frequency transmitters and two receivers to TG 7.5. This equipment was activated by the Contractor when the Nan Camp was first established and provided two HF circuits for phone and teletype communications between Nan and Elmer during the build-up stage of REDWING. These circuits, however, could not meet the demands ofa fullscale test operation. Therefore, in conjunction with AEC communication personnel, a series of path-proving tests were conducted over a period of approximately one year, which determined the feasibility of VHF transmission. For the primary radio link between Eniwetok and Bikini Atolls, a multipule channel VHF system was designed. This system is illustrated in Figure 2-164. The Contractor drew up specifications for three KW amplifiers and high gain antennas, Figure 2-162. CHAPTER II, SECTION 4 which were purchased. The AN/TRC-24 multichannel radio equipment was obtained from military sources on a loan basis. Sigtot with Samson units were used to provide on-line crypto operation of teletype messages, and AFSAY 806 voice cyphony equipment was used to provide security of the voice channels. These devices were installed and later serviced by military personnel because of security reasons. Two antennas each were required at Elmer and Nan—onefor transmitting and one for re- ceiving. The antenna system consisted of four dipoles fed in phase and mounted one-half wave length from the vertex of a 60-degree corner reflector. The corner reflectors at Elmer were mounted on top of individual 130-foot steel towers. The corner reflectors at Nan were mounted between two members of type 2400 (X-braced) towers located at the 235’-9” and the 264’-3” levels of the 300-foot tower at Station 70. Equipment for VHF System Page 2-179