Furuno TZT9 Operator's Manual page 163

7. FISH FINDER
[Zero Line Range]: This feature adjusts the transmission line so that the line disap-
pears when [Zero Line Rejection] is turned on. The effective range is 1.4 to 2.5. For a
long tail, increase the value. If the transmission line does not disappear, lower the TX
power (DFF3 only).
[Transducer Draft]: Set the distance between the transducer and the draft line to show
the distance from the sea surface (Setting range: 0.0 to 99.9 ft).
[Salt Water]: Select [ON] to use this equipment in salt water.
[Fish Finder Source]: Select the sounder used, among DFF1, BBDS1, DFF3, FCV-
1150 or DFF1-UHD.
[Transducer Setup]: Select the method to setup the transducer, manually or by select-
ing the model number.
[Manual]: Enter high/low frequencies and TX power.
[Model Number]: Select the type of the transducer connected.
[Transmission Power]: Interference can appear on the screen when the fish finder on
your ship and another ship have the same TX frequency. To prevent this interference,
lower your TX power and ask the other ship to lower their TX power. The setting range
is 0 to10. 0 is off and 10 provides the highest TX power. For DFF1-UHD, the setting
range is [OFF], [Minimum], or [Auto].
[External KP]: Turn on to sync with external keying pulse.
[Bottom Level HF (LF)]: The default bottom level setting (0) determines that two strong
echoes received in sequence are bottom echoes. If the depth indication is not stable
in the default setting, adjust the bottom level here. If vertical lines appear from the bot-
tom echo in the bottom lock display, lower the bottom level to erase the vertical lines.
If you can not identify the fish near the bottom from the bottom echo, increase the bot-
tom level.
[Gain Offset HF (LF)]: If the gain setting is wrong, or there is a difference in the gain
between the low and high frequencies, you can balance the gain for the two frequen-
cies here.
[Auto Gain Offset HF (LF)]: If the auto gain offset is wrong, or there is a difference in
the gain between the low and high frequencies, set an offset here to balance auto gain
for the two frequencies.
[STC HF (LF)]: Delete unnecessary echoes (plankton, air bubbles, etc.) near the sur-
face that hide the fish near the surface. The setting range is 0 to 10, and 0 is off. 10
deletes unnecessary echoes from the surface to approximately 16 ft. Make sure you
do not use more STC than necessary, because you can erase the small echoes near
the surface (DFF3 only).
[Frequency Adjust HF (LF)]: You can adjust the TX frequency of both the low- and
high-frequency transducers. Use this feature when your fish finder and another fish
finder operate on the same frequency, causing interference. Change the frequency of
your transducer by enough percentage points to remove the interference (DFF3 only).
[TX Pulse HF (LF)]: The pulse length is automatically set according to range and shift.
Use a short pulse for better resolution and a long pulse when detection range is im-
portant. To improve resolution on zoom displays, use [Short 1] or [Short 2]. [Short 1]
improves the detection resolution, but the detection range is shorter than with [Std]
(pulse length is 1/4 of [Std]). [Short 2] raises the detection resolution, however detec-
7-18