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Metz Manta-6 Marine VHF Antenna Full Technical Specification :

Standing Wave Ratio (SWR) is less than 1.2:1. This is a measure of the radio performance loss in the antenna. An SWR of 1:1 would be perfect, no loss; 1.5:1 is considered good, 1.2:1 is exceptional.

Antennas are available with different levels of “gain”, measured in decibels - dB. Whereas a 6dB or even a 9dB antenna, are available, a 3dB gain is ideal for mast head applications and is always used for this application. Why? Well, imagine that the signal is like a fat doughnut surrounding the antenna. In higher gain systems this doughnut becomes flatter and more focused. This would be fine if the boat never heeled, either as a result of sailing or by being bounced around in waves. Unfortunately, with even a modest angle of heel the flatter doughnut ends up pointing either at the sea surface, or at the sky, instead of at the horizon. The fat doughnut aims a larger portion of the signal at the horizon at any given angle of heel. So, fat is good, hence 3dB gain.

Frequency range 156 – 163 MHz. This covers all marine VHF channels as well as some weather transmitting frequencies.

No ground plane needed. Some antennas, known as 5/8 – wave antennas, look very similar to the ½ wave type such as the Metz Manta-6, but require a metallic ground plane directly below them to develop proper radiation characteristics.

Weighs only 8 ounces (225 grams): Clearly, for masthead applications weight is important.

Installation advice :

The SO 239 socket accepts the standard PL-259 plug. For masthead applications where the run is less than 20 meters we recommend RG8X (RG-mini) coaxial cable. For marine applications it is important that the coax has a copper braid, preferably tinned. Note that TV antenna coax cable is absolutely not suitable for VHF antenna use – it has a 75 ohm resistance, whereas VHF marine antenna cable must have 50 ohm resistance.

The OCL and ISAAF recommend the above cable selection in order to meet their requirements for VHF antenna performance in Category 1 ocean races.

Metz Communications is based in the USA and has been manufacturing antennas since 1977.

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J. Schofield Ltd (Salty John Boat Products Yacht Chandlers).
Oakwood House, Cartford Lane, Little Eccleston, Preston PR3 0YP, UK

Boat Products + Yacht Chandlery

PHONE: +44 (0) 1995 672556 FAX: +44 (0) 1995 672425 E-MAIL: info@saltyjohn.co.uk