Bottom Level; Tvg Level - Onwa KES-700 Operator's Manual

b) If two transducers are installed via the
switch box EX-8, set XDR FORE field
and XDR AFT field to 50 kHz or 200 kHz,
according to actual installation.
3. Reset the power.
Note: The default settings in the
TRANSDUCER SETTING window are N/A.
At the first power-up after installation, the
window appears to set transducer(s).

4.3 Bottom Level

If the depth indication is unstable or the
seabed cannot be displayed steadily
notwithstanding the adjustment of the
control panel, you may adjust the
bottom echo level.
CAUTION
If the level is set too low, the FE-700
may not be able to distinguish the
bottom from fish echo and the
depth indication m ay be unstable
and if set to high the depth
indication does not appear.
1. Press the MUTE ALARM key three times
at the EXTENSION MODE. The start-up
screen appears and shortly thereafter the
BOTTOM LEVEL display appears.
*: Either 200 kHz or 50 kHz is displayed
depending on which frequency is used.
2. Set the level with the [+] or [-] key. The
default level is 80.
3. Press the POWER switch to finish the
adjustment. Wait about 5 s and then turn
on the power again.

4.4 TVG Level

TVG (Time Varied Gain) compensates for
propagation attenuation of the ultrasonic
waves,reducing surface noise to provide a
smooth display. The TVG lowers receiver
sensitivity at the time of pulse emission
and gradually increases it with time, there
by making objects of same reflectivity at
different depths appear at the same intensity
or colors on the display. The TVG working
depth is down to approximately 150 m on
the 200 kHz system and 350 m on the 50 kHz
system. Outside this range the echoes from
the seabed and fish schools are received in
full level.
There is no perceivable deterioration in
performance.
1. Press the DRAFT key three times at the
EXTENSION MODE display. The TVG
SELECT window appears.
2. Set the TVG curve with [+] or [-]. The
default level is 5. Attenuation compensation
curve is at 20LogR curve.
3. Press the POWER switch to finish the
adjustment. Wait 5 s, and then turn it on
again.