Eagle Electronics FISHMARK 320 - Manual (Page 61)

57
Sonar chart in regular grayscale mode, left, and in FishReveal mode,
right. Notice how shallow fish formerly hidden in the surface clutter
become visible in FishReveal mode.
NOTE:
Water conditions vary greatly, and that affects sonar performance.
Under certain conditions, FishReveal will show you more fish than
normal grayscale mode, but the reverse will be true in other circum-
stances. We suggest you become familiar with both modes so you can
best match your sonar's performance to the current water conditions.
Frequency (Change Transducer Frequency)
(SeaFinder 320DF only)
The "DF" in your unit's name refers to its dual-frequency transducer,
which operates with both 200 kHz and 50 kHz. The 200 kHz frequency
has a 12
° cone angle and the 50 kHz frequency has a 35° cone angle.
The default frequency is 200 kHz, which is best for use in shallow water
(about 300 feet or less). This frequency is the best choice for about 80
percent of the fresh and salt water sport fishing applications. When you
get into very deep salt water, 300 to 500 feet or deeper, the 50 kHz fre-
quency is the best choice.
The 200 kHz transducer will give you better detail and definition, but
less depth penetration. The 50 kHz transducer will give you greater
depth penetration, but a little less detail and less definition. (Remember,
all sonar units typically read deeper in fresh water than in salt water.)
Visible
fish
Fish
not
visible
Fish
arch
Fish
arches