Airmar R109C-LH 2kW CHIRP Thru-Hull Low/High Transducer

The R109C-LH is the narrow-beam high-frequency variant of Airmar's 2kW thru-hull transducer family, and it sits at the top of the line as the HARD CORE deep-water tool. The LH designation stands for Low + High, calling out the dual-band CHIRP configuration: a low-frequency element sweeping 38 to 75 kHz for deep-water tracking and a narrow-beam high-frequency element sweeping 130 to 210 kHz with an 8-to-4 degree beamwidth. The narrow high beam is what separates the R109C-LH from the wide-beam LHW variant of the same chassis. Where the LHW spreads coverage across the upper water column, the LH concentrates the high-frequency energy into a tight beam that resolves individual bait, game fish, and bottom structure at depth. For commercial fishing operators, deep-water canyon trolling, and sea-mount tracking on offshore boats 40 feet and above, the narrow-beam LH is the configuration the serious operators run.

The low-frequency element handles the deep-water side. CHIRP sweeping from 38 to 75 kHz with a 19-degree port/starboard beam and a 10-degree fore-aft beam, narrowing to 10 and 5 degrees at the upper end of the band. Maximum depth on the low band runs to 6,000 feet (1,829 meters), which is plenty for canyon-edge work and most offshore deep-drop applications. The narrow-beam high band tops out at 1,500 feet (457 meters), which is exceptional depth performance for a high-frequency channel. The narrow 8-to-4 degree beamwidth is what concentrates the energy and lets the high band reach those depths. Total usable bandwidth across both elements is 117 kHz, covering the popular 38, 50, and 200 kHz fishing frequencies plus everything in between. Modern CHIRP-capable sounder modules can sweep either band or both simultaneously based on what the operator wants to see.

The thru-hull mounting style is the standard offshore install. The transducer stem protrudes through the hull with the included fairing block on the outside hull face cleaning up water flow at speed. The fairing handles deadrise angles up to 22 degrees, which covers most modern sportfish and trawler hulls. For boats with deeper deadrise, a custom fairing block would be needed. Hull material is unusually flexible for a thru-hull: the R109C-LH is compatible with all hull materials including fiberglass, aluminum, steel, and wood, which makes it usable on a wider range of commercial and recreational boats than most thru-hull transducers.

This SKU specifically is the bare-wire variant. The cable ends in unterminated wire pigtails rather than a manufacturer-specific connector. That's the right pick when you're hardwiring directly to a sounder module's input terminals or routing through a junction box mid-cable. For chartplotters with specific connector requirements, the connector-equipped variants of the same element are alternative SKUs. The fairing block is included with this SKU, which the connector-equipped variants may or may not include depending on configuration. The urethane potted housing handles long-term saltwater immersion without degradation, and the patented Xducer ID auto-detect technology lets compatible chartplotters automatically identify the transducer type and load the correct calibration tables without manual setup.

The 33.3 pound (15.1 kg) weight requires structural hull integrity around the install point, which is standard on boats 40 feet and above. A marine electronics installer with thru-hull experience is the right person for the install, since the hole through the hull, the bedding details, and the fairing alignment all need to be done correctly. We can recommend an installer in your area for the bedding work, and we can spec the right sounder module pairing for the transducer before you order. Warranty service for the R109C-LH goes through Airmar's standard authorized network.

One more pattern worth knowing about choosing between LH (this SKU), LHW (Low + High Wide), and LM (Low + Medium) configurations of the same base transducer family. The LH is the narrow-beam deep-water tool. It's the right pick when you want to resolve individual fish and bottom structure at deep range, the 200 kHz neighborhood is where you want detail, and you don't need wide under-boat coverage. The LHW spreads the high-frequency coverage across a 25-degree wide beam for finding pelagic fish in the upper water column and is the more versatile sportfish choice. The LM trades the high band for a medium band, which is what you want when most of your fishing is deeper than 200 feet and you want resolution at canyon depths. Commercial fishing operators and serious deep-water captains typically run the LH because the narrow-beam target separation is what professional sounder picture interpretation depends on. Mixed-use sportfish boats often pick the LHW. Dedicated deep-drop and sea-mount captains often pick the LM.