CHAPTER Il, SECTION 6 the ships and Building 204 on Nan and Building INTERFERENCE DETECTION SERVICE. 488 on Elmer. Also, a two-channel cyphony link to the BOXER was maintained using additional AN/TRC-24 equipment. The Bikini shore station used three element high gain, corner reflec- Since a considerable portion of the scientific diagnostic data was obtained by Sandia through the use of microwave telemetry, it was of prime beamed ference by radars and other radio signals. At Elmer a Military-furnished interference measur- tors located on the 300-foot tower at Nan and on the evacuation rendezvous area. Coverage was excellent to the maximum 45 miles required. By the use of station patch panels, ship’s circuits were patched through the interatoll tropo system to Eniwetok during the evacuation periods. At Elmer a similar installation was made, excluding the cyphony circuit. Corner reflectors located on the 125-foot tower provided full coverage to the lagoon and the WAHOO operational areas. Charts 2-23 and 2-24 show predicted field strength contours of this system for the ship-to-shore service at the Eniwetok and Bikini Atolls respectively. Again, the contours are based upon the expected field strength at the horizon in the direction of maximum antenna gain. The equipment used proved to be very reliable in operation. HIGH FREQUENCY CIRCUITS. During the Weather and Rad-safety Station construction effort contact was maintained with construction parties and the supply ships by the use of a high frequency net. Daily voice contact importance to protect these channels from inter- ing and locating set was installed in the REDWING Station 1518 tower. This installation protected Sandia circuits on the adjacent 300foot observation tower. A similar installation was made at Building 204 on Nan which was later transferred to Johnston Island. Portable equipment covering 0 to 300 megacycles was operated at both atolls to locate radio interference to any radio facility reporting difficulties. The interference detection team identified the offending signal, pinpointed its location, and advised JTF-7 of regulatory action. Considerable difficulty was experienced at first in bringing the older type Military-furnished equipment up to satisfactory operating standards. Thé equip- ment used for the microwave protection during HARDTACK lacked the sensitivity and opera- . ting efficiency of later model equipment. TELEPHONE. as Nauru. This circuit continued to be used to contact the ALOTO after her arrival. Vertical radiators and ET-10 transmitters were added at During the interim period and build-up phase for Operation HARDTACK, the same telephone equipment that had been in use during the two previous Operations remained in service. A three-position manual PBX anda single tollboard were in use at Elmer. This equipment was obsolete and in poor condition. For the operational phase of HARDTACK, a dial exchange TELEVISION STATION. increased traffic load. It is felt that more room for the telephone operators, including a relief WXLE-TV, an Armed Forces Television Station, was operated and maintained by H&N of morale among the operators. was maintained with all stations ranging as far Elmer and Nan. In addition to providing communications to the ship, the HF channels were used for unattended monitorservice of the Bikini radio installation during the interim period. personnel. The facility consisted of a combined studio and transmitter station in Building 488 on Elmer and a laboratory in Building 330, where film was stored and processed for showing and shipment. The station operated from 1730 to 2255 hours daily and from 1330 to 2255 hours on Sundays and holidays. Coverage of the FredElmer-David area was excellent, with very good voice and video quality. Television sets were supplied to recreation halls and day rooms. Program material consisted of taped commercial network shows and sports events. During the interim period, local productions included a weekly Chaplain’s Hour and an_ occasional Hawaiian musical group. During the operational period, local features were limited to a daily news summary and a five-minute stock market report each evening. With the arrival of a TG 7.3 trailer packaged TV installation at Nan, WXLE-TV was given permission by AFRTS to loan the regular film shipments to the Bikini facility. Page 312 was installed at Elmer to serve the anticipated operator’s lounge, would have resulted in a more efficient telephone program and a greater degree At Janet a one-position manual PBX was placed in service coincidental with the opening of the camp. A similar installation was made at Yvonne for that camp. Components of the 700- line dial exchange for Elmer and the three 70- line dial sub-exchanges for the off-islands began arriving in late November. The Elmer dial exchange was installed in the newly constructed Building 224, and was cut over to dial operation on 1 February 1958. Yvonne was converted to dial operation on 24 February 1958, and Janet became the final link in an integrated dial system for Eniwetok on 6 April 1958. There were 30 inter-office dial trunks between the main exchange on Elmer and the Military-operated dial exchange on Fred. Also, 10 automatic dial trunks and 6 operator-controlled ring-down trunks functioned through the inter-atoll Tropo- spheric System to Nan. Initially, there were 8 inter-office trunks between the Elmer exchange and both Janet and Yvonne. It became necessary