Transducers for Fishfinders

Transducers for fishfinders and chartplotters

The transducer is the component that truly determines the quality of the sonar images returned by a fishfinder or chartplotter. It is the element in contact with the water that sends the sound pulse and receives its echo, converting it into an electrical signal that the display processes and turns into an image. With the same chartplotter, choosing the correct transducer directly affects achievable depth, image resolution, and the ability to use advanced sonar technologies such as side scanning or real-time viewing.

This category includes Garmin transducers compatible with chartplotters and fishfinders from the Striker, Echomap, and GPSMAP lines, divided by technology family: the all-in-one GT series transducers, which integrate traditional CHIRP, ClearVü, and SideVü into a single component, and Panoptix transducers, dedicated to real-time scanning, including the Panoptix PS70, the most advanced model in the range for deep-water three-dimensional scanning.

Product types

GT series all-in-one transducers

The GT family includes transducers that integrate traditional CHIRP sonar, ClearVü, and, in the most complete models, SideVü functions into a single component. They are available in versions with different power outputs and frequencies, designed to meet different requirements in terms of operating depth and image detail.

The GT20-TM is a traditional CHIRP transducer combined with ClearVü, with 500 W power, 77/200 kHz frequencies in traditional mode and 455/800 kHz in ClearVü mode, and a stated maximum depth of approximately 1900 feet in traditional mode and 750 feet in ClearVü. The GT51M-TM adds SideVü mode, with CHIRP frequencies of 80/160 kHz in traditional mode at 600 W and 260/455 kHz in ClearVü/SideVü at 500 W per channel. The GT24UHD-TM and GT54UHD-TM raise image resolution with higher frequencies: ClearVü at 800 kHz delivers more detailed images of structure, while dual-frequency 455/1200 kHz SideVü provides higher-definition side scanning. The GT56UHD-TM is the top model in the all-in-one series, with 350 W power in standard echo mode and UHD frequencies for ClearVü and SideVü.

GT transducers are available in transom-mount versions (mounted on the transom or on the trolling motor shaft) and thru-hull versions, for flush-mount installation or installation with a fairing block on boats with deadrise. The choice between the different versions depends on the hull type, cruising speed, and available installation position on board.

Panoptix LiveScope transducers

Panoptix LiveScope transducers (LVS32 and LVS34 models) are designed for real-time sonar scanning. They consist of a black-box sonar module (GLS 10) and the actual transducer, with a plug-and-play connector for quick integration with a compatible Garmin chartplotter. Mounting brackets are available for Perspective mode, for installation on the trolling motor shaft, or for pole mounting. LiveScope technology can be paired with an all-in-one GT transducer to have CHIRP, ClearVü, SideVü, and LiveScope scanning on the same chartplotter at the same time.

Panoptix PS70: the transducer for deep-water 3D scanning

The Panoptix PS70 is the most advanced model in the Panoptix range, designed for deep-water fishing and for users who require maximum definition when scanning the bottom and locating fish. It is an 800 W thru-hull transducer, powered by Garmin RapidReturn technology, that delivers real-time 3D images with a minimum refresh rate of 10 frames per second, up to 8 times faster than previous Panoptix models, maintained even at a depth of 300 meters.

The PS70 offers four display modes selectable from a compatible GPSMAP chartplotter: LiveVü Down mode, which lets you observe small bait schools and predators in real time with a 120-degree beam angle; traditional mode, for use as a standard CHIRP transducer; Triple-Beam mode, which simultaneously returns data from starboard, center, and port relative to the vessel’s course; and RealVü 3D history, which builds a three-dimensional representation of the bottom and water column while the boat is moving, useful both for locating targets and mapping large areas of bottom.

The True Motion 3D function allows RealVü 3D mode to follow the vessel’s actual course (Course Over Ground) when reconstructing the bottom, rather than remaining anchored to a fixed point. The PS70 also integrates an AHRS sensor that provides image stabilization, compensating for vessel motion to maintain a consistent view even in rough sea conditions. The sonar beam has a width of 120 by 8 degrees, useful for quickly locating bait and fish across a wide section of the water column.

From a construction standpoint, the PS70 is a stainless-steel thru-hull transducer that can be installed flush-mounted, in a pocket, or with a fairing block for hulls with a deadrise angle of up to 20 degrees. It is also compatible with the Quickdraw Contours function, which allows large bottom areas to be surveyed and recorded down to 300 meters, sharing the collected data with the Garmin Quickdraw community or saving it directly on your chartplotter.

How to choose the transducer

Choosing the correct transducer depends on several factors, which should be evaluated together before purchasing.

The first element to consider is compatibility with the chartplotter or fishfinder you already own. Not all transducers are compatible with every Garmin line: for example, UHD transducers such as the GT56 or GT54 require a chartplotter capable of processing high-definition frequencies, while some Striker series models only support GT51 and GT52 transducers and are not compatible with UHD versions. The Panoptix PS70 requires a compatible GPSMAP chartplotter in order to use all of its display modes.

The second element concerns the type of mounting available on board. Transom-mount transducers are installed on the transom or on the trolling motor shaft, and are the easiest solution to install on small and medium-sized boats. Thru-hull transducers, such as the PS70, require a hole in the hull for flush or pocket mounting, or the use of a fairing block to compensate for the hull bottom angle; they are generally the preferred choice for larger boats or permanent installations.

The third element is the required operating depth. Entry-level GT series transducers, such as the GT20, reach approximately 1900 feet (580 meters) in traditional mode, while ClearVü and SideVü functions operate at more limited depths, generally down to a few hundred meters. The Panoptix PS70 stands out for its ability to provide real-time 3D images down to 300 meters, a relevant feature for offshore or deep-water fishing.

The fourth element is the required sonar technology. Users who only need to know depth and have a basic bottom reading can choose a traditional CHIRP transducer. Those who want to distinguish structures below and alongside the boat more clearly need a transducer with ClearVü and SideVü. Those who require real-time viewing of moving fish, both vertically and horizontally, should choose a Panoptix LiveScope transducer or the Panoptix PS70, the latter being especially suited to deep-water three-dimensional scanning.

Technologies and technical features

CHIRP (Compressed High-Intensity Radiated Pulse): sonar technology that sends a pulse across a continuous range of frequencies, rather than on a single fixed frequency. This allows better target separation and sharper images than traditional single-frequency sonar.

ClearVü: downward scanning technology that returns a high-definition image of what is directly below the boat. In entry-level GT transducers it operates at 455/800 kHz, while in UHD versions (GT24UHD, GT54UHD) the frequency increases up to 800 kHz with higher resolution.

SideVü: side-scanning technology, available on GT51 and later transducers, that returns images of the bottom and structures on both sides of the boat. In UHD versions, the dual frequency reaches up to 1200 kHz for higher side-scan definition.

RapidReturn: exclusive Panoptix PS70 technology that significantly increases the real-time image refresh rate, up to 8 times faster than previous Panoptix transducers, guaranteeing a minimum of 10 frames per second even at a depth of 300 meters.

RealVü 3D: three-dimensional scanning technology available on the Panoptix PS70, which reconstructs the bottom and water column in real time while the boat is moving, allowing targets to be located and a three-dimensional map of the scanned area to be built.

Image stabilization (AHRS): attitude and heading reference sensor integrated into the Panoptix PS70 that compensates for boat motion caused by rough seas, maintaining the consistency of the returned sonar image.

Quickdraw Contours: function that allows custom bathymetric maps to be recorded while navigating. With the Panoptix PS70, surveying is possible down to 300 meters, a greater value than with standard GT transducers.

Practical use

While underway, the transducer works together with the chartplotter or fishfinder to provide a continuous reading of depth and bottom contour. GT transducers with traditional CHIRP are sufficient for general navigation and for identifying depth in real time. When greater detail of submerged structures or fish schools is required, ClearVü and SideVü functions offer a richer representation, useful for planning a route or identifying points of interest.

The Panoptix PS70 is ideally suited both to high-level coastal fishing and offshore fishing, where image refresh speed and three-dimensional scanning capability allow the behavior of fish and bottom structure to be followed in real time, even at depths where traditional transducers lose effectiveness. LiveVü Down mode is useful for observing the area beneath the boat in real time while trolling or at anchor, while Triple-Beam mode expands lateral viewing without requiring a separate SideVü transducer. RealVü 3D history, combined with the True Motion 3D function, is particularly useful when navigating in search of new fishing grounds, because it progressively builds a three-dimensional map of the bottom following the vessel’s actual course.

Installing the correct transducer requires attention to mounting position and angle. Transom-mount transducers are generally easier to install but more exposed to hydrodynamic turbulence at high speeds. Thru-hull transducers, including the PS70, generally offer a more stable reading at high speeds, but require a more structured installation, possibly with a fairing block to compensate for hull angle.

Available brands

Garmin is the exclusive brand for the transducers in this category. An American company founded in 1989, Garmin designs and manufactures transducers compatible with the entire range of chartplotters and fishfinders in the Striker, Echomap, and GPSMAP lines, from GT series all-in-one models to Panoptix transducers for real-time scanning, including the Panoptix PS70.

Conclusion

Choosing the right transducer directly affects sonar image quality and the operating depth that can be achieved, regardless of the quality of the chartplotter it is paired with. GT series transducers offer complete solutions for most navigation and fishing uses, with CHIRP, ClearVü, and SideVü technologies available in different power and frequency combinations. For users who require superior performance in real-time scanning and deep-water fishing, the Panoptix PS70 is the most advanced solution in the range, with RapidReturn technology and RealVü 3D three-dimensional scanning down to 300 meters.

In all cases, checking compatibility between transducer and chartplotter before purchasing remains the most important step to obtain the performance stated in the technical specifications of each model.