A marine VHF whip antenna depends for its performance on proper design and build-quality. That tin can at the bottom of the antenna contains the DC shunted coil that must be precisely tuned to the proper resonance. Getting this bit of the design and build right is the difference between an antenna that performs well and one that doesn’t.
The Metz range is based on a heavy gauge stainless steel shell which encloses the 16 AWG coil wound around a substantial form. The coil assembly is sealed in a solid epoxy compound. This build method allows prolonged transmission without danger of coil distortion as the antenna heats up.
Lower quality antennas have fibreglass bodies enclosing light gauge coils and inadequate forms all sealed in a waxy substance. This flimsy internal construction leads to distortion of the coil as the antenna heats up when transmitting, which changes the antenna characteristics, leading to poor performance and even damage to the radio.
To survive in the marine environment the antenna needs to be strongly built of appropriate materials – look for stainless steel components, including both the body and the whip. How the antenna is built internally isn’t so obvious – you’ll need to rely on reputation and a good warranty.
You don’t need to pay through the nose for top quality construction: the Metz Manta is similar in price to ordinary fibreglass bodied antennas and substantially lower in price than some other stainless bodied antennas. And it carries a lifetime coil warranty. Check it out at the Salty John on-line shop