Introduced in 2011 as the next-gen tool for precision echo-sounding, Airmar’s new CHIRP transducers really are a step up the evolutionary ladder in the world of recreational fishfinders. Most readers know of Airmar as the “transducer people”, since they currently manufacture the thru-hull, transom mount and in-hull transducers for the majority of marine echo sounders, fishfinders and black box sonars sold in the USA. Not content to rest on their past laurels, the Airmar engineering team has recently launched a new series of game-changing CHIRP transducers that are compatible with the new wave of broadband and spread spectrum fishfinders that are being introduced by leading marine electronics manufacturers. The combination of these next-gen echo sounders in collaboration with the new Airmar CHIRP transducers will give coastal anglers a more enhanced look at the submarine world like never seen before. While broadband transducers will certainly enhance conventional echo sounder performance, maximum benefit will be achieved when they are driven by the next-gen CHIRP, FM and Spread Spectrum fishfinders.
These revolutionary transducers continuously operate across a range of frequencies, rather than at the traditional dedicated frequencies of 50 kHz or 200 kHz that most anglers have used in the past. When transmitting at dedicated frequencies, targets that are smaller than the 50 kHz or 200 kHz sound wave may be undetected and therefore not shown on the fishfinder display. With CHIRP, the transmitted signal covers a wide band of frequencies, providing significant improvements in the ability to detect all targets in the water column. More bottom and water column area is covered as the beam width constantly changes from narrow to wide while the transducer is "chirped" across the specified band.
Research has shown that some fish species return better signals at specific frequencies, which makes CHIRP systems the optimal choice for fish-finding. Additional benefits include 25 to 50 times more energy on targets, enhanced detail and resolution, precise location (within inches) of fish in the water column or tight to the sea bed, no noise interference, and extreme deep-water sounding below 10,000 feet.
Depending on the model, these transducers contain a low-frequency ceramic array capable of running at either 28 to 60 kHz or 42 to 65 kHz. To complement the deep-water detection, either a high-frequency or medium frequency broadband ceramic element is also included in the transducer array. The high-frequency ceramics operate in the 130 to 210 kHz band. The medium-frequency ceramics cover the 85 to 135 kHz band, which has historically been used in commercial fishing, especially 88 and 107 kHz, due to certain fish species being better detected at these frequencies.
This medium band has rarely been used in the sport fishing market, until now. Medium-frequency benefits include the ability to sound deeper than the high-frequency, along with better target resolution than the low-frequency. All low and high-frequency broadband transducers will carry an “LH” suffix after the model name while the low and medium-frequency transducers will carry an “LM” suffix after the model name.
The B265LH thru-hull transducer is a 1 kW unit that offers eight internal, broadband ceramic elements. The low-frequency can be chirped from 42 to 65 kHz while the high-frequency chirps from 130 to 210 kHz. Beam widths range from 18 degrees to 25 degrees on the low-frequency band and six degrees to ten degrees on the high-frequency band. This transducer is optionally available as a B265LM, with low and medium-frequency (85 to 135 kHz). Both units include a high-precision water-temperature sensor for accurate sea-surface temperature readings, critical to fishing success when you are tournament angling and looking for that “magical” temperature break that frequently holds bait and gamefish. Both transducers also come with a high-performance fairing for crystal clear bottom imaging at vessel speeds over 30 knots.
Other versions of this same 1 kW, eight-element CHIRP transducer include the model M265LH and M265LM, which can be installed in the bilge of a solid fiberglass boat without drilling any holes in the hull. There’s also the transom-mount TM265LH and T265LM that is best suited for smaller outboard and I/O powered vessels. All of these transducers have similar performance specifications to the B265 model detailed above.
The low-profile B75 and B175 CHIRP transducers should also be very popular with anglers, since they are probably the easiest to mount. The B75 is 600W and the B175 is a 1 kW transducer and both are “mushroom” type thru-hulls that protrude only a fraction of an inch below the boat’s hull to minimize interference when underway and limit any potential mishaps when striking a partially submerged object. Frequency band, transducer hull angle and beam width vary with model. Airmar B75 and B175 low-profile thru-hull transducers are available with pre-set internal element angles at 0-, 12-, & 20-degree of deadrise (with a low, medium or high frequency option) to best match the deadrise angle of your boat, which will provide the optimum perpendicular angle to pinpoint fish directly under your vessel’s keel.
With dozens of models to choose from, MSRPs on Airmar CHIRP transducers start at $740. Street prices for the 265 series of 1 kW transducers will range between $1,400 to $1,600, depending on the model.