So, what does pitting man versus the machine tell us? First off, it’s pretty clear that Broadband
radar does, in fact, have a pretty darn
impressive brain. If you have one on
your boat, chances are you’ll be best
served by leaving it on auto mode. What
about other brands? I haven’t personally experienced any other unit that can
self-adjust this well, but it’s easy enough
for you to test your own radar for yourself. All you need is a clear day, a strong
pair of binoculars, and a range of strong
and weak targets to choose from. You
might be surprised at the results — and
even if you’re not, chances are good
you’ll learn a thing or two about how to
best adjust your own unit.
When it comes to fishfinders, in
average conditions on average days,
you’re likely to see beneath the surface
best in auto mode. But the moment
you aren’t satisfied with the view,
start pressing buttons. Many different
anomalies in weather and water composition can deceive these devices, as
we saw with the hurricane-riled waters
of the Chesapeake. I’ve also observed
modern units being fooled by algae
blooms, heavy jellyfish populations,
dense schools of fish, and aerated surface waters.
To effectively manually adjust your
fishfinder’s sensitivity, start by increasing range to double the water’s depth.
Then increase gain until a second bottom echo appears on-screen. Shift back
to the proper range setting, and you
have a good starting point.
If most of the clutter you see is at
the top of your screen, increase the
STC setting next. If not (or after boosting STC), reduce gain until mid- and
deep-water clutter is reduced. As long
as you continue seeing fish and receiving a solid bottom reading, slowly bump
the gain down a notch at a time until
fish are still present and clutter is not.
If you’re in deep ocean waters, you lose
bottom and/or fish readings as you
make these adjustments, and you have
a multi-frequency unit, try shifting to
a lower frequency and repeating the
above process. And remember, if some
arrogant, overbearing automated voice
tells you that the human brain is outdated, don’t believe it. Yet. — L.R.