KJM AIS Antennas
KJM AIS Antennas: Built for the Open Water
When it comes to on-water safety, few pieces of equipment matter more than a reliable AIS antenna. The Automatic Identification System (AIS) lets vessels broadcast and receive critical position, speed, and identity data — and the antenna is the linchpin of the entire system. KJM has earned a respected place in marine electronics by focusing on exactly this kind of purpose-built, performance-first hardware.
KJM is dedicated to providing the finest in shipboard VHF and AIS antennas, with products built to withstand the harsh marine environment and designed by experts with over three decades of experience in the marine industry. That depth of expertise shows up in the details of every antenna they produce.
The A430-AIS and A431-AIS Product Lines
KJM's flagship AIS offerings center on two closely related models. The A431-AIS marine AIS/VHF antenna builds on the success of the A430-AIS and includes 20 feet of low-loss RG-8/X cable permanently attached to the antenna and a high-quality solder-type PL-259 connector with stainless steel ferrule — making it ideal for stand-alone AIS applications or combination VHF/AIS installations where a splitter is used.
The A431-AIS features commercial-grade fiberglass construction, brass and copper elements, a high-gloss polyurethane finish, and a stainless steel ferrule with 1"-14 thread. These aren't cosmetic choices — brass and copper elements provide superior conductivity and corrosion resistance in salt air and spray, while thick-walled fiberglass stands up to UV, vibration, and rough seas where lesser antennas fail.
For AIS-equipped vessels, the antenna features a wide 7 MHz bandwidth, allowing efficient use for both VHF and AIS applications. This dual-band capability means mariners running both a VHF radio and an AIS transceiver can use KJM's antenna as the backbone of a combined communication system.
3 dB Gain and AIS Signal Standards
AIS transceivers require a vertical antenna with 50-ohm impedance and a gain of no less than 3 dB to properly receive and transmit signals. KJM's AIS antennas are engineered to meet this standard precisely — the A431-AIS delivers a 3 dB gain in a compact 4-foot white form factor that fits virtually any powerboat, cruiser, or sailboat installation.
A 5-Year Warranty That Stands Behind the Product
All KJM antennas are backed by a 5-year warranty, so you can communicate with confidence. In the marine antenna category, a 5-year coverage commitment reflects genuine confidence in materials and build quality — and gives boaters the peace of mind to focus on navigation rather than worrying about gear reliability.
Flexible System Integration
KJM's AIS antennas are designed to work within a broader onboard electronics ecosystem. For boaters who want to share a single antenna across multiple systems, KJM offers the SPL100 Band Splitter, which allows a marine VHF antenna to simultaneously receive AM/FM and AIS signals while also allowing a connected marine VHF radio to transmit and receive. This makes it easy to build a clean, single-antenna installation without compromising performance on any channel.
Whether you're fitting out a new vessel or upgrading aging antenna hardware, KJM's AIS antennas offer a compelling combination of commercial-grade construction, dual-band versatility, and long-term warranty protection — everything a serious mariner needs to stay connected and safe on the water.