l-second timing lights synchronized with WWV, are recorded on 35m
etrip film. Further details are given in Technical Manuals (References
pide
The AFOAT=-1 operational stations were essentially sferics direc-
tion-finding stations similar to the description above but with a wider
bandwidth (8 to 12 ke).
Force Base, Bangor,
A coincidence system was used between Dow Air
e and Austin, Texas so only signals in a pre-
determined azimuth (-5 degrees) would present a distinctive mark on
the filn,
OPERATIONS
« The equipment for the experiments at the Pacific Proving Ground was placed in a trailer and shipped as deck cargo. The
trailer served as the main AFOAT-1] electromagnetic close-in station and
contained all the equipment except that for determining world times of
detonation, The trailer site selected was Enyu Island, on the southeastern portion of Bikini Atoll, and across the lagoon from the detonation points. The timing equipment was erected in the AFOAT-1 headquarters on Parry Island, Eniwetok Atoll,
Because of the expected high yield of Shot 1, the equipment on Enyu
was not manned but was actuated by an Edgerton, Germeshausen and Grier
(EGG) relay timer.
The radioactive debris from Shot 1 drifted over the
trailer, making it impossible to enter the area after the detonation
until the debris had decayed to a reasonable value. After a week the
trailer on Enyu had cooled sufficiently for handling, so all equipment
was removed and relocated on Runit Island, Eniwetok Atoll, about 300 km
from Bikini. The equipment was installed in a bunker on Runit where it
was manned for the balance of the Bikini shots.
For Shot 6, which was
detonated on Eniwetok, 23 km from the bunker, the recording equipment
on Runit was unmanned but was actuated by an EGG relay timer.
Station locations. Figure 4 shows the locations of the electromagnetic stations, the agency responsible for the measurements at each
place, and the distances from each station to Bikini and Eniwetok.
For
the most part for distant stations, locations already in use by NBS,
DRL, AWS and AFOAT-1 were utilized. At Shemya, Thule and Kirknewton,
however, site surveys were made by AFOAT-1 personnel. Insofar as possible, sites were chosen on east-west and north-south orientations in an
attempt to get some idea of the propagation differences due to a daylight path, a dark path, and auroral zone transmission.
Special Measurements. Between detonations, low-frequency trans-
mitters, NSS (Annapolis, Maryland), NLK (Arlington, Washington), NPM
(Oahu, T.H,), and GBR (Rugby, England) were monitored on an agreed-upon
schedule, in order to obtain information on various transmission paths
at various times, There was also an attempt to monitor sferics to coincide with the routine AWS four-minute recording scheduled every six
hours, beginning at 0030Z.
Alert Notifications.
The experimental equipment installed at the
Close-in locations, and at most of the distant locations, had a limited
16
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