Benthowave Instrument Inc.

BENTHOWAVE INSTRUMENT INC. Acoustic Transducer & System 

Line Array Hydrophone

Hydrophone ArrayHydrophone Array: Amplitude Shading or WeightingHydrophone ArrayLine Array Hydrophone

Benthowave's line array hydrophones are designed for uses in passive SONAR, listening systems, near-field measurement and calibration. A planar array (such as T shape, + shape...) or a volumetric array (3D array) can be set up with two or multiple BII-7020s for direction-finding Sonar system. To search the known sound sources, a band pass filter is recommended to work with BII-7020 series hydrophone to reject the noises.

BII-7021 integrates the sound pressures along its surface and support amplitude shading/weighting. The integration of the sound pressures along a line can be used in measurement of acoustic radiation field, trouble-shooting, maintenance and development of transducers and arrays, and researches in theoretical acoustics such as boundary element acoustics, Green's function, Helmholtz integral and Rayleigh's integral, etc...

BII-7022/3/4 averages of sound pressures along the Line Array, and supports amplitude shading/weighting.

How to use BII-7020 series as discrete array element in low frequency sound reception?
To achieve narrow beam width at low frequency, multiple BII-7020s can be wired in series with underwater connectors to extend the array length. For example, to test 1kHz signals underwater, seven BII-7020s as discrete array elements are in series with 0.75m spacing to achieve beam width of 15°.
When ordering BII-7020 series as an array element, you shall specify cables and underwater connectors (one male, the other is female) on both ends of the hydrophone, and specify the cable length.

Technical note: for long line array, to avoid high pull force acting on the underwater connectors and the array cables, a reinforced rope with high pull strength shall be used along the array, and the array cables are tied on the reinforced rope with soft cotton rope (avoid scratching or damaging cable jacket). Make sure that ONLY reinforced rope withstand high pulling force during field operation. BII does not sell reinforced rope and soft cotton rope, which usually is available in your local stores.

BII-7020 Line Array Hydrophone: Passive SONAR & Listening Systems

Suggested Application  
Directional Hydrophone, Increasing Signal-to-Noise Ratio
Towed Array, Broadside Array, End-fire Array
Tracking of Acoustic Tags in Marine Fisheries and Animals
Direction-finding Sonar System
Researches in Acoustics
Sound Bearing Systems, Measurement of Target Bearing
Passive SONAR / Listening Systems, Sonobuoy, PAM System
Near-field Calibration and Measurement
Hydrophone Calibration
Trouble-shooting, Maintenance and Development of Transducers and Arrays
Frequency Range: 1Hz to 160kHz;
Beam Pattern: Donut-shape
Very Low Interference to Acoustic Field Under Test
Small Sensing Elements for Detection of Broadband Signals
Long Cable Driving Capability
Related Products  
BII-7010 Low Noise Preamplified Broadband Hydrophone BII-7660 Multibeam SONAR Transducers: 2D Imaging Sonar
BII-7140 Low Cost Hydrophone Array / Streamer Element BII-7630 Phased Array: Underwater Imaging


Line Array Hydrophone Hydrophone ArrayLine Array Hydrophone
Line Array Hydrophone BII-7021 BII-7022 BII-7023 BII-7024
Signal Processing: Integration of Sounds along the Line Array. Averaging of Sounds along the Line Array. Averaging of Sounds along the Line Array. Averaging of Sounds along the Line Array.
Operating Frequency: 1Hz to 160 kHz 1Hz to 160 kHz 1Hz to 10 kHz 1Hz to 160 kHz
Array Element:  Continuous Continuous N, Customized. Continuous
Acoustic Aperture: Φ9.5 x L (mm) Φ9.5 x L (mm) Φ9.5 x L (mm) Φ9.5 x L (mm)
Element Spacing: N/A N/A d ≤ λ/2, Customized. N/A
Channel Number: 1 1 1 1
Beam Pattern: Donut Shape Donut Shape Donut Shape Donut Shape
Along-length Beam Width: No Shading:
No Shading:
2*arcsin(1.4*λ/(PI*dN))  No Shading:
Cross-length Beam Width: Omnidirectional Omnidirectional Omnidirectional Omnidirectional
Voltage Sensitivity:
(Without Shading)
-195.5 dB V/μPa -195.5 dB V/μPa -195.5 dB V/μPa -201.2 dB V/μPa
Output Type: Differential Differential Differential Single Ended
Capacitance (nF): 18/L 0.18*L 0.18*N 6.6*L
Diameter ΦD: Φ21mm Φ21mm Φ21mm Φ21mm
Length (mm): L, Customized L, Customized (N-1)*d L, Customized
Transmitting Sound: No No No Yes
Driving Voltage: N/A N/A N/A 100Vpp
Miscellaneous: BII-7020 Series Linear Array Hydrophone
Shading/Weighting: 1. Default: No
2. Dolph-Chebyshev
3. Binominal
Side Lobes: 1. No Shading: ≤-13.4 dB;
2. Dolph-Chebyshev: ≤-40.0 dB;
3. Binominal: No Side Lobe.
Receiving face: Cylinder
Signal Conditioning: Hydrophone Preamplifiers Not included, order separately.
Signal Filter Not included, order separately.
Maximum Operating Depth: 300m
Mounting Options: 1. Default: Free Hanging (FH)
2. Thru-hole Mounting with Single O-ring (THSO)
3. Thru-hole Mounting with Double O-ring (THDO)
4. Bolt Fastening Mounting (Plastics): (BFMP)

5. Bolt Fastening Mounting (Stainless Steel): (BFMSS)
6. Thru-hole Mounting + Free Hanging (THFH)
Transducer and Hydrophone Mounting for more detailed information on mounting/installation.
Cable: 1. Shielded Cable with two conductors (ΦD=6.5mm) (SC)
2. RG58 Coax 50Ω (Coax)
Cable Length: 1. 10m (Default)
2. custom: up to 100m.
Cable Connector: 1. Default: Wire Leads (WL)
2. BNC male (BNC)
3. 3.5 mm (⅛″) TRS Plug (TRS35)
4. ¼″ (6.35 mm) TRS Plug (TRS635)
5. XLR Plug (Unbalanced wiring) (XLRU)
6. MIL-5015 Style 3 Pins (5015)
7. Underwater Mateable Connector (UMC)
8. Custom (custom)
Operating Temperature: -10°C to +60°C
Storage Temperature: -40°C to +60°C
How to Order: Click How to Order.
Hydrophone Wiring: Click Hydrophone Wiring for detailed wiring information.

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