Teledyne SeaBat T Series, Operator'S Manual, Page: 45 / 152

ACTIVE SONAR USAGE
SeaBat T-Series Subsea Operator's Manual Page 33 January 31, 2019
Version 7
Table 4: TVG Formula
G
L
for R < R
L
TVG =
G
+
S
P
[log
10
(
R
) -1] + 2(
α
/1000)
R
for
R
≥
R
L
83 for
R
≥
R
M
Where:
α
=
G
=
G
L
=
R
=
R
L
=
R
M
=
S
P
=
Absorption loss in dB/km
Extra gain from RxGain menu item
An internally calculated gain applied until the TVG begins
Range in meters
Lowest range (in meters) from where the TVG formula operates
Range in meters where the gain has reached highest possible value (which is 83dB)
Spreading loss coefficient
NOTE
The values of
R
L
,
G
L
, and
R
M
are not accessible, but
R
L
is in generally limited to a few meters
from the sonar. It is recommended to subscribe for record 7010 in order to obtain the TVG.
For details on environmental conditions such as absorption and spreading, see section 6.4 below .
For instructions on how to adjust this setting, refer to the RESON Sonar UI User Manual ( see
Appendix E Reference Documentation ).
6.2.5 Frequency Selection

400kHz for highest resolution at shorter ranges.

200kHz for greater range performance.
For general hydrographic surveys, the switch from 400kHz to 200kHz at either end of the scale in
FM mode (or 420kHz to 190kHz in CW mode) may be necessary between depths of 80m and
120m depending on conditions. Frequency selection between the upper and lower limits may be
made in steps of 10kHz.
NOTE
Adjusting the frequency affects beam width. Reducing the frequency produces wider beams,
increasing the frequency produces narrower beams.
For instructions on how to adjust this setting, refer to the RESON Sonar UI User Manual ( see
Appendix E Reference Documentation ).
6.2.6 Pulse Length
For instructions on how to adjust this setting, refer to the RESON Sonar UI User Manual ( see
Appendix E Reference Documentation ).
NOTE
The Pulse Length adjusts itself automatically when Tracker is selected (see also section 6.3.2 below ).