CHAPTER II, SECTION 3 eras were mounted. A 2-cubic-foot metal box containing camera controls was buried in the ground 5 feet behind the bench. The cameras were used to photograph rocket launchings at Station 261.01 and were located 200 feet from the working point of this station. Timing sig- nals consisted of minus 15 minutes, minus 15 seconds, and minus 5 seconds. One cubic yard of concrete with an average 28-day strength of 2,750 psi was used. STATION: PURPOSE: SITE: USER: PARTICIPATION: CONSTRUCTION: 913 Fireball Photography George DOD-9 18 3-22-56/4-11-56 were set, the pipes were lined by transit and grouted in place. STATIONS: PURPOSE: SITES: 1214.01 thru 1215.12 Threshold Detectors Helen to Irene Causeway and Janet USER: DOD-12 PARTICIPATION: 5 and 23 Design criteria called for User-furnished detectors clipped to 1-inch steel cables, each approximately 4,000 feet long located at Stations 5 and 23. Construction of these stations was not started per User request. This station was a 15’ x 11’-6” x 6’-10” high frame-type plywoodshelter set on a concrete slab and having a tarpaulin roof. A pipe beam supported by end columns was located along an open side of the station. Four vertical posts which supported cameras were furnished and attached to the beam by the User. Power was furnished by a 10 KW, 110-volt, single-phase, 60-cycle generator which was protected with sandbags. Minus 15 minutes, minus 15 seconds, and minus 5 seconds timing signals were provided. A total of 5 cubic yards of concrete was poured, with an average 28-day strength of 3,600 psi. STATIONS: PURPOSE: SITES: 1210.01 thru 1212.12 Threshold Detectors Yvonne and Janet USER: DOD-12 PARTICIPATION: 5, 6, 7 and 24 CONSTRUCTION: 4-7-56/5-17-56 These stations were 3-inch pipes about 8’ high set in concrete, with double and single 3%” round top crossarms attached. Stations 1212.02 through .04 had cable in the centers for holding the pipes in case of shearing from blast effects. The bottom crossarms were set at an elevation of plus 7 feet. The User attached detectors to the crossarms with cable clips. Several of these stations participated in various events, requir- ing their location at varying distances from the zero stations, which in turn necessitated that some be constructed on the reef and others on land. Stations 1211.01 through .11 were used conjointly with Stations 252.01 through .11. No timing signals or power were required. A total of 4 cubic yards of concrete was used. Due to the blast effects of previous events, it was ne- cessary to replace five of the pipes for later shots. This replacement was accomplished by prefabricating 4’ x 4’ x 3’-high concrete blocks with embedded pipes and then transporting them to thesite of installation. After the blocks Figure 2-60. STATIONS: PURPOSE: SITE: USER: Station 1220.01 1220.01 thru 1220.07 Alpha Detectors Yvonne DOD-12 PARTICIPATION: 6 and 7 CONSTRUCTION: 4-2-56/4-19-56 These stations required 26’ x 10’ x 4’-thick reinforced concrete foundations with partially embedded structural steel frames, which were used for mounting 30-ton concrete blocks containing a collimator and detectors. New foundations and steel bracing were required in order to orient the stations on the working point of Stations 6 and 7. It was necessary to pour the foundations in two pours with a construction joint in the center of the block to enable setting the steel frame on a solid base rather than suspending it during the concrete pour. Page 2-79