Above: Furuno tested its FCV1200 BB with Airmar's 2 kW R209 across a wide range of frequencies. (Depths are in fathoms and equal 190 to 200 feet.) Changing or "slewing" the frequency helps pinpoint a transducer's optimal settings. At about 200 feet, this transducer (note: operating ranges are 33 to 60 kHz and 130 to 210 kHz) returns the best resolution at 160 kHz on the high-frequency side and 40 kHz on the low end. Tuning a transducer can mean the difference in seeing fish or missing them.
Anglers who buy new fish finders may not question which transducer best fits their fishing. But with today's high-definition and side-imaging sonars, transducers have truly become a key component in the system.
In fact, because of more cooperative work between sonar makers, such as Simrad, Furuno, Raymarine, Lowrance and Garmin, and the country's primary marine-transducer manufacturer - Airmar (www.airmar.com) - transducers now help drive fish-finder innovation.
For anglers, that very simply means a better way of seeing the water column and more personalization based on how you fish and what fish you target.
As with most technology, the cutting edge for marine-transducer development belongs to the military and commercial industries. Some concepts are secret; some are merely pricey. But applications have trickled down to high-end recreational fishermen, and that trend should continue.
Some say that within two years, small-boat anglers may be able to dial a specific frequency - anywhere from 28 to 200 kHz - on their sounder. Some transducers are already capable of sending and receiving varying frequencies, but the majority of recreational-grade sounders can't adjust. Or they can use up to three frequencies but not the complete range.
"I was talking to a big commercial installer in Massachusetts, and he was telling me how the swordfish guys use one frequency and the tuna guys use another," says Mark Reedenauer, Airmar's product marketing manager. "It's also a secret among tournament teams. They know certain game fish and bait species show up at specific frequencies, and if the other guys can't see the fish, they have an advantage."
Furuno, which makes commercial sounders and transducers along with its recreational products, builds scientific-grade machines that use a range of frequencies that can display species differently and help differentiate bottom substrate and sediments at significant depths, says Matt Wood, Furuno's sales manager. On the high-end recreational side, Furuno's DFF3 black-box unit for NavNet vx2 or 3D ($2,695) and the FCV 295 ($3,295) and FCV 1150 ($5,195) - both dedicated fish finders - allow anglers to adjust frequencies when paired with the proper transducer.