Overview

The Garmin GA 38 is a GPS and GLONASS antenna for boats that need a dedicated external satellite receiver feed for compatible onboard electronics. It uses a waterproof housing rated to IPX7 and a low-profile footprint that measures 91.6 mm in diameter and 49.5 mm tall, so it tucks neatly onto a cabin top, hardtop, radar arch, or similar mounting spot.

Mounting can be done on a pole, directly on a flat surface, or under a fiberglass deck (on the underside). These configurations are commonly used when the helm electronics sit inside a pilothouse, under a hardtop, or below deck and you want the GPS antenna placed where it can keep a clearer view of the sky.

Key features

• Tracks GPS and GLONASS satellites for position input to supported marine electronics.
• Waterproof housing rated to IPX7 for real-world deck spray and washdowns.
• Low-profile body: 91.6 mm diameter x 49.5 mm height.
• Mounting options for pole, surface, or under-deck installation under fiberglass.
• 10 m (32 ft) antenna cable, with connector style depending on the selected configuration.

Variants

This product is offered in multiple configurations to match different Garmin-compatible systems and housing colors.

Configurations vary by the intended device compatibility and the cable connector style (BNC-SMA or BNC-BNC), plus the external housing color. Core GA 38 function remains the same across the range: GPS and GLONASS reception in an IPX7-rated, low-profile antenna housing.

• 010-13305-20: Compatibility for Cortex V1 & M1, color Black. This version is matched to Cortex installations that use the BNC-SMA cable connection, with a black housing for a consistent look on deck.
• 010-13305-00: Compatibility for Cortex V1 & M1, color White. This version is matched to Cortex installations that use the BNC-SMA cable connection, with a white housing that blends into light-colored topsides.
• 010-12017-30: Compatibility for Garmin VHF, AIS & Chartplotters, color Black. This version is intended for compatible Garmin systems that use a BNC-BNC external antenna connection, with a black housing for darker mounting surfaces.
• 010-12017-00: Compatibility for Garmin VHF, AIS & Chartplotters, color White. This version is intended for compatible Garmin systems that use a BNC-BNC external antenna connection, with a white housing for lighter mounting surfaces.

Installation and setup

For best results, mount the antenna where it has the most open view of the sky and where it is less likely to be shaded by masts, hardtop supports, antennas, or radar structures. If you route the cable through a deck or hardtop, seal the pass-through properly and leave a small drip loop so water does not track down the cable into the interior.

Under-deck mounting is intended for the underside of fiberglass decks. Avoid placing it under metal structures or dense equipment areas that can block satellite reception.

Compatibility and fit

Before ordering, confirm which connection your system expects. Cortex V1 and M1 installations use the GA 38 configuration with a BNC-SMA cable, while compatible Garmin VHF, AIS, and chartplotter setups use the GA 38 configuration with a BNC-BNC cable. Housing color is a cosmetic choice and does not change the antenna function.

Use cases on board

This antenna is a solid fit for cruising and fishing boats where the main electronics are mounted inside the helm and you want the GPS antenna outside for steadier reception. It also suits refits where an older external GPS antenna is being replaced and you want a clean, low-profile footprint on deck.