Settings and performance of acoustical instruments
Fishing gear
|
Frequency |
38 kHz |
120 kHz |
|
|
Basic range (m) |
0-100/0-250 |
0-100 |
|
|
Bandwidth |
3.0 kHz |
3.3 kHz |
|
|
Pulse length |
0.6 msec. |
1.0 msec. |
|
|
TVG and gain |
20 logR -20 dB |
20 logR 0 dB |
|
|
Recorder gain |
7 |
4 |
|
|
Transmitter power |
External transmitter |
High |
|
|
Transducer dimension (ceramic) |
8° x 8° 30 x 30 cm |
10 circular |
|
|
Discriminator |
5-7 |
- |
|
|
Source level + voltage response |
139.2 dB |
112.2 dB |
|
|
Measured |
31 August 1982 |
31 August 1982 |
|
|
Integrator treshold |
A |
0.5 |
0 |
|
|
B |
0.5 |
0 |
|
Integrator gain |
A |
20 dB x 10 |
10 dB x 10 |
|
|
B |
20 dB x 10 |
10 dB x 10 |
|
Depth intervals (m) |
A |
4-50 |
4-50 |
|
|
B |
50-250 |
50-100 |
|
|
(Varying with depth) |
|
|
|
Bottom stop |
|
ON |
ON |
|
Demersal trawl: |
High opening shrimp and fish trawl with rubber bobbins.
Headline 41 m. Height during trawling approximately 6 m. Mesh size in the wings
40 mm, gradually reduced to 20 mm in the codend. |
|
|
|
|
Pelagic trawl: |
Capelin (“Harstad”) trawl. Width about 30 m.
Vertical opening about 15 m. Meshsize at codend 21 mm. |
