Furuno CSH-5L/CSH-8L - Manual (Page 34)

2. FINE TUNING THE SONAR PICTURE
2-6
2.5.4 Rejecting interference with TX cycle
When other sonars of the same TX frequency as own sonar are near, an
interference ring caused may be displayed. To erase the interference ring from
the screen, reduce the TX CYCLE setting.
Interference
Tx cycle high Tx cycle lowered
Interference rings
1. Press the MENU key.
2. Use the [RANGE] control to choose [MENU MODE] at the top of the screen.
3. Use the [GAIN] control to choose SONAR to display the SONAR menu.
4. Use the [RANGE] control to choose TX CYCLE.
5. Use the [GAIN] control to set TX cycle. The setting range is 0-10 and the
higher the figure the longer the TX cycle.
6. Press the [MENU] key to close the menu.
Note:
When the sonar is used in shallow waters with the range set between 100
m and 200 m and the TX cycle at “10”, a previously reflected echo may
appear at close range. In this case reduce the TX cycle to “7 or 8” to
reject it.