7 Dec 1973
- waterbody:North Atlantic OceanGrand Turk Island; U.S. Naval Facility
NOTES: Notes on tape: "Time 1856 Zulu 7Dec1973." Notes from analysis log: "Face Cassette number side down, rewind. Moderate level ambient. Some distant ship traffic. Humpback: Neg.; Minke: Pos.; No. Heard: 1? No. Trains: 6; Need for further analysis: Yes, loud, strong, close. Notes: Starting off 022 with a moderate level thump train. At 158 hear intermittent thump beats and random click sounds. At 278 strong thump train - strongest thus far heard on all first 3 reels. At 422 hear thump train weak. Few random CRACK noises suddenly lead into thump train. At 479 good strong thump train, best yet. Again at 663 sec how the crack click sounds lead off the start of a train."
[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