13 Jan 1974
- waterbody:North Atlantic OceanGrand Turk Island; U.S. Naval Facility
NOTES: Notes on tape: "Time 0310 Zulu 14Jan1974" [This should be 2210 local time, 13Jan1974. First 1:30 removed - high noise, no signal.19Dec2003 CB] Notes from analysis log: Cassette number side down - rewind. Ambient noise level mod.; distant ship traffic, increasing noise level at times. Humpbacks: Pos?; Need for further analysis: No. Notes: At 031 maybe a humpback groan. Minke: Pos.; No. Heard: 2; No. Trains: 12. Need for further analysis: Yes - check 465, maybe different (slap type thump train) and stops short end of train. Notes: At 080 a strong level thump train, at 233 a moderate to strong level thump train, at 465 a mod level thump train again at 512 (may have additional frequency content in thumps) at 543 a different one? At 602 a strong one - he stops abruptly - normally they fade out. At 658 a mod level thump train, at 670 this guy stops short, again 703, again 730, 734, 753 random thumps."
[Notes from analysis log for all tapes in the GRANDTURKS series: "Six half-hour background recording samples on selected days for a period of 53 days... to detect the arrival and departure of the Humpback whales (via sounds) for the season in the Caribbean Sea, Mouchier, Navidad and Silver Banks...There are indications that recordings used a 420Hz Low Pass Filter. Recording equipment used was a Realistic model CTR-19. Cassette recorder operating on 110VAC, Freq 60-10,000Ha.. The Realistic recorder is poor recording frequencies below 60Hz as evidenced by spec sheet and sonograms. There is 120 & 180Hz electrical interference 'splatter' on some tapes. In certain cases when the ambient is low, the gain of the systems are raised hence we have heavy interference masking wanted signals. This could be caused by a fluorescent light fixture near the recording system? I doubt that it is in the hydrophone pre-amp network." See analysis log for more details.] SEAOCEAN