Simrad EY500, Instruction Manual

Page: 228 / 262

Calibration
26
P2260/E
Select the Layer Menu/Layer-1 Menu and set:
Type: Pelagic
Range (layer thickness L) See table below
Range Upper: See table below
Sv Threshold -100 dB
No. of Sublayers: 1
Frequency
kHz
Range L
m
Range Start
m
2TL
dB
18 50 3975 96
38 20 990 80
120 10 195 61
200 5 147,5 59,5
Range settings and transmission loss for different frequencies
Start the noise - speed trial with the vessel in a fixed position. Make a short
echogram recording and an integration table for the same interval. Print a
marker line when starting the recording and give the line a number that at
the same time is logged in the noise-speed report form at the end of this
document.
Print a second marker line at the end of the recording, connect the propeller
and increase the speed to 2 knots. When the vessel has reached a stable
speed, make a new echogram recording interval and integration table for the
same interval. Continue the same procedure at 2-knot intervals until
reaching maximum speed. Use marker lines to separate the different
intervals. When at maximum speed, disconnect the propeller as quick as
possible and print marker lines for each 2 knots as the speed decreases
towards 0.
If the noise level quickly decreases towards the level at 0 knots as soon as the
propeller has been disconnected, this means that the noise is generated by
the propeller. If the recording at decreasing speed is more or less equal to the
same noise level at increasing speed, the cause is probably flow-noise.
If the increase in level is propeller noise and this substantially reduces the
performance of the sounder, repeat the tests with different combinations of
pitch and propeller speed if possible, to find the most favourable conditions.
When making echogram recordings at different speed levels, select the Test
Menu/Transceiver and read the noise power P
N
re 1 W. Enter readings in the
same form at the end of this appendix.