Simrad ER60 - REV B Operator's Manual page 37

Figure 4 Target
strength of a 60 mm
copper sphere
850-164692 / Rev.B
Copper spheres
Frequency Diameter
(kHz) (mm)
12* 45.0
18 63.0
27 42.0
38 60.0
49* 45.0
50* 45.0
70 32.1
120 23.0
200 13.7
710 10.3
(*) = same sphere
The curve for the 38 kHz sphere is given as an illustration.
1400 1420
60 mm copper sphere, 38 kHz
Calibration using ER60
Only one frequency may be calibrated at a time. Thus, you must
uninstall all transceivers in ER60 except for the one you intend
to calibrate. When you have calibrated this frequency you must
uninstall the transceiver, install the next transceiver, and
calibrate this frequency, and so on until all frequencies are
calibrated.
All the different combinations of pulse duration and transmitter
power that will be used during normal operation of the echo
sounder must be calibrated.
First, create a well organised file directory for the calibration
results. Example:
c:\er60\calibration\2003\38kHz\0.256msec\
Operational procedures
TS
(sound speed = 1490 m/s) (dB)
--40.4
--34.4
--37.9
--33.6
--36.4
--36.2
--39.1
--40.4
--45.0
--50.5
Pulse duration (ms)
1440 1460 1480 1500
SOUND SPEED (m/s)
3.0
0.3
1520 1540 1560
29