Marine HF antenna for vessels over 11 metres (36 feet)


A 5.5 metre (18ft) heavy duty whip, similar to type 18W, designed to provide highly efficient communications in the HF Band range from 2-30 MHz, both in the transmit and receive modes, where deck mounting is required.

Specially suitable for large yachts, the 18B is neatly mounted by means of a nylon base insulator with chrome bronze flange support and stainless steel bolt deck feed through insulator [fits decks to 19mm (¾) thick], which allows direct underdeck connection.

The antenna is constructions from tempered aluminium alloy tubing and is protected by a high durability epoxy based coating resistant to chemical attack, abrasion and the effects of ozone and ultra-violet radiation. To facilitate transport, the antenna breaks down into two sections [base: 3.65m (12ft); top: 1.85m (6ft)], which screw together on a self locking taper which slip together and fasten with 2 stainless steel self tapping screws.

It is available unloaded or resonant at a single frequency (the highest to be used, normally 2.6, 4.6, 6.3, 8.3 or 10 MHz). For operation on frequencies other than the resonant frequency, the difference is made up in the ATU.


HF Marine Band 2-30 MHz

Length: 5.5 metres (18 ft)

Pattern: Omnidirectional

Polarisation: Vertical

Base Diameter: 25.4cm (1 in) (radiator)

Frequency Range: Pretuned to frequency or frequencies required, or unloaded 2-30 MHz with suitable ATU

Wind Loading: 4.9 kg at 100 km/h (10.8 lbs at 60 mph)
8.3 kg at 130 km/h (18.3 lbs at 81 mph)

Power Capability: 800W PEP for unloaded top sections, 600W PEP for normal loaded top sections; 400W PEP for trapped top sections; higher power to order

Mounting: One integral base insulator and 12.7cm (5 in) chrome bronze flange with ‘O’ ring seal between insulator and flange, and 4 x 6.75mm (17/64 in) mounting holes (bolts not supplied).

Centre feed through hole: 15.8mm (5/8 in) dia.

Connection: Underdeck to lug on feedthrough bolt
Packed Weight: 5 kg (11 lbs) with mounting