Honda HE-670 Operation Manual page 11

HOW TO DISTINGUISH THE FISH SCHOOL
Important is comparison between display of fish school and catch
It is possible to distinguish the fish sort by display of fish school to some extent. But
even if fish sort is same, it's form making school is different according to difference of
fishing ground and difference of time (day and night, four seasons, variation of current).
The important thing to distinguish the fish sort is to know the sort according to their
fishing ground or fishing period and to find the useful point on the display by comparing
between display of fish school and actual catch.
HOW TO DISTINGUISH THE FISH VOLUME
As the harder density the transmitted wave is reflected strongly, you can distinguish the
density of fish school according to the strength of reflected echo (that is, different color).
Normally we tend to think the larger fish school on the screen the most fish volume. But
when fish school are located at the shallow depth and the deep depth, fish school at the
deep depth is displayed bigger than at the shallow depth. Because the transmitted wave
spreads wider as it goes deeper and the reflected wave spreads wider as it goes
shallower. As this result, the deeper becomes the wider the width of fish school becomes
on the screen. The important thing to distinguish the fish volume is to judge it according
to size of fish school and the strength of reflected echo (color) while you keep "the
deeper fish school stays the bigger picture is displayed" in your mind.
Reflected
wave
Fish school A
Fish school B
6
Fish school A picture
(shallow)
Fish school B picture
(deep)