Modification and Utilization of AN/SSQ-41 Sonobuoys for the Collection of Volume Reverberation Data from Aircraft

• Main Authors: Davis, Edward E., Parham, John B., Kelly, Clyde E.
• Other Authors: NAVAL OCEANOGRAPHIC OFFICE NSTL STATION MS
• Format: Text
• Language: English
• Published: 1968
• Subjects: Undersea and Antisubmarine Warfare; Acoustic Detection and Detectors; *SONOBUOYS; *AIR DROP OPERATIONS; CALIBRATION; HYDROPHONES; ACOUSTIC EQUIPMENT; MODIFICATION KITS; RELIABILITY(ELECTRONICS); ANTISUBMARINE WARFARE; AUTOMATIC GAIN CONTROL; AUDIO AMPLIFIERS; RESPONSE; SCATTERING; REVERBERATION; AN/SSQ-41; MOST PROJECT-2; North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/AD0849291; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0849291

AN/SSQ-41 Sonobuoys were modified, calibrated and tested for utilization in the collection of volume reverberation data from aircraft. The electronic modifications involved removal of an AGC circuit and gain adjustments in the amplifier stages. The sonobuoy hydrophone array was also modified to provide for omnidirectionality. A calibration circuit was added for checking system linearity as well as for direct reading of absolute reverberation levels from collected data. Test and feasibility studies using the modified sonobuoys were conducted in the western North Atlantic. The acoustic data obtained in these studies were analyzed in one-third octave bandwidths in the frequency band between 0.8 and 4.0 kHz. Reverberation levels were determined by using a calibration pulse transmitted by the sonobuoy and a scattering strength computed. The results of the analyzed data indicate scattering strength generally increases with increasing frequency with a knee or peak occurring between 1.0 kHz and 2.0 kHz.