AGC turns the sonar's gain down automatically when echoes are strong, so a heavy bottom or dense bait does not drown out weaker marks beside it.
At a glance
- AGC near and AGC far: 0 to 10
- A higher value suppresses more
- The distances are set in the System menu
About 5 minutes. Part of Run the CSH-10.
What it does
AGC near suppresses gain inside the near AGC distance to reduce unwanted echoes there. AGC far does the same beyond the AGC far distance. Both run from 0 to 10, and raising the value suppresses more.
When to touch it
If a strong return, such as bottom or a heavy cloud of bait, hides smaller marks around it, raise the matching AGC value a step at a time. If marks you want start to disappear, you went too far: lower it again. Gain brightens the whole picture; AGC evens it out.
Near, far and the defaults
The manual's default AGC area is within 270 m (preset P1), with 200 m for some presets and 90 m for another. Remember the gain lesson's note that Furuno's own documents give slightly different default distances, so check your unit.
Watch it done
Furuno USA publishes these CSH-10 videos. They play from YouTube when you press play.
Operator Orientation Part 6: near gain, far gain, AGC near and AGC far
Check yourself
Three questions
Sources
- CSH10 Operator's Manual: Section 2.2.1
- CSH10 Explanation of User Settings: AGC near and AGC far
This lesson summarizes Furuno's public documents in our own words. Limits and settings differ by model and software version, so your own manual and your installer have the last word. OmniCSH is an independent project, not a Furuno program.