Raymarine a65 Installation And Operation Instructions Manual page 179

Frequency adjustment (CHIRP sonar module in
non-CHIRP mode)
When using a CHIRP sonar module in CHIRP mode (Low Chirp,
Med Chirp or High Chirp) the frequency cannot be adjusted. When
using a CHIRP sonar module in a non-Chirp mode (e.g. 50 kHz
or 160 kHz) the frequency at which the transducer is transmitting
can be adjusted.
With the CHIRP sonar module set to a CHIRP mode (e.g. Low Chirp
or High Chirp) the CHIRP sonar module will sweep the transducer's
available frequency range in each ping.
With the CHIRP sonar module set to a non-CHIRP mode (e.g. 50
kHz or 160 kHz) the CHIRP sonar module can adjust the frequency
at which the transducer is transmitting. The advantages of being
able to adjust the transmit frequency include:
• Optimization for particular species of fish and water conditions.
• Avoiding interference from other sonar operating nearby (at the
same frequency).
• Use of wide or narrow beam on a particular transducer.
The graph below depicts the adjustment (selection of a specific)
frequency when using a CHIRP sonar set to 160 kHz.
CHIRP sonar module frequency
-50%
120 130 140 150 160
1. Frequency adjustment range.
2. Transducer characteristics.
3. Operating (center) frequency.
Adjusting the fishfinder frequency (CHIRP sonar module in
non-CHIRP mode)
When connected to a CHIRP sonar module set to a non-CHIRP
mode you can manually adjust the transmit frequency.
From the fishfinder application:
1. select Menu.
2. Select Frequency settings.
3. Select either Tune Freq 1 or Tune Freq 2 as required.
The Frequency adjust slider bar is displayed:
4. Adjust the slider to the required value.
5. Select Back to close the adjust frequency slider bar, or
6. Select Ok to set the adjust frequency to automatic.
Note: When manually adjusting the frequency the actual
frequency of operation is not displayed, the fishfinder application
title bar displays the transducers center frequency.
Using the fishfinder
+50%
170 180 190 200 210 220
1
2
3
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