6.2.3
Instroment Performne
Tse aicrobarographs located at Jonestoa Island 2id mot experience any cecd-
nical difficulty.
The French Frigate Shoals station incurred a defective time-
mark-generator output but aaintained 10-second tise aorks.
This established
sutiicient reference for deteraining travel time of the blast wave.
The dot
Teccrdings did oot furnish iorernally coasistent pressure anplitodes or arrival
Cimes, but observations by other agencies gave enough inforsatioa so that a
reasonable interpretation could be aade.
The sensing beads wre all] calibrated prior to their being positioned at
their respective survey points, anid they possessed balance-dan capability
throughout the tests.
A. H + 5 ainutes during the Teak event, an UP Gie instruction was transmitted from Johnston Island to French Frigate Shoals aod Oahu.
This meant thar
operators at these stations were to change from their 120 microbarograph sets
on the 500-microbar range.
The French Frigate Shoals station received the in-
struction UP OXE, bur instead of changing the 140 range to 400, the operator
changed the 400 range to 1200.
This decision was based on the blast intensity
as te saw it, which resulted in a wider range of blast wave-recording capability
but aade analysis somewhat more difiicule.
The Qahu station did not receive the
instruction because of communications blackout.
French Frigate Shoals and Oahu were given 400 set ranges for the Orange
event with no provision for changes.
Vor