07/01/2013

iUSBL mounted to pole on Sheila B about 1m deep in water. Power set to high (PL3) and detection threshold to 10dB (PDT 10). Gain was also high. Routine "false" hits every so often throughout the day. At 09:37 (see session log or positive_hits_1.txt) around 70 ranges came through that seemed somewhat reasonable. They mysteriously disappeared despite driving back through the area. The LF acoustic modem was lowered over the side for the 10:00 wakeup and no modem tones were heard. This is not the first time tones have been missing however. 
A less satisfying string of range hits came later in the day around 12:00. These values were not quite as believable and behaved much in the same way as the first set - after attempting to scan the area multiple times, there were no more hits to be found. 


\\Atlas\ProjectLibrary\901006.BEDS\BEDS.Data\2013_07_01_Sheila_B

See 2013_07_01_sheila_b_BED#1_search_3km_scale.jpg for a ship track and other notes
See positive_hits_1.txt and positive_hits_2.txt for a subset of range hits
See /other_ship_track_formats/2013_07_01_sheila_b_track_all.csv for a human readable timestamp and location to manually sync position to hits. 
See 2013_07_01session_log.txt for full sonardyne iUSBL interaction log.