SELECTING A VHF ANTENNA |
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VHF antennas are a crucial part of your VHF installation, and understanding how they work and how to select the correct antenna can greatly improve your ability to communicate with other boaters and shore stations. The main purpose of a VHF antenna is to provide a radiator for the power that the transmitter in the radio produces, and to radiate this energy in the correct direction. Antennas also have to be enclosed in a weather-protected enclosure (or be made of a corrosion resistant metal and plastic) and must be able to withstand the substantial forces generated by a boat pounding in heavy seas.
Selection criteria:
dB Rating: An antenna’s dB rating (or antenna gain) indicates the apparent increase in transmitting power due to its ability to focus energy. Antennas with a high dB rating concentrate energy perpendicular to the antenna shaft in a field that is shaped like a disk. This makes your radio signal appear stronger to receiving stations around you.
It also reduces the amount of energy transmitted above or below the antenna, which can be a problem if your boat is pitching or rolling in seas. A concentrated signal can actually fade in and fade out as the boat rolls and pitches. As the dB rating of the antenna increases, so does the height of the antenna, but the horizontal angle diminishes. The broad radiation pattern from a low dB antenna allows a sailboat to heel over and still send signals toward the horizon. Sailboats should use a 3dB antenna mounted at the top of the mast whenever possible.

Gains and losses: A gain increase of 3dB means a doubling of signal strength: 6dB is a fourfold increase, and 9dB is an eightfold increase. The actual watts transmitted doesn’t increase; it’s just that the power is concentrated, much like a reflector on a flashlight, in a more concentrated beam. Therefore, a radio with a 6dB antenna will sound like it has a larger transmitter than the same radio with a 3dB antenna.
Elements inside the antenna: There are three main styles of electrical elements: those using cut lengths of coax cable, those using a simple brass radiator, and those using a more complicated copper and brass radiator. While all provide acceptable performance, better antennas use brass or copper inside the fiberglass for maximum strength and durability.
So what kind of range can I expect?
Marine VHF radios for recreational boats are limited to 25 watts of output so, unlike Single Sideband or Ham radios, you cannot boost your range with a more powerful transmitter.
VHF radios operate on a line of sight principle between stations, meaning that the signals do not bend around obstructions or over the horizon.
Antenna height, more than any other factor, determines how far you can transmit. An antenna mounted up high can “see” farther over the horizon.
Antenna gain is important. If several otherwise equal radios try to contact a single receiving radio, the higher gain antenna is the one the receiving radio will hear.
Transmit (1,5m water level)
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Receiving Antenna Height
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Antenna Height
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13 cm
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25 cm
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65 cm
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2,5 m
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6 m
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13 cm
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8 km
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11 km
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15 km
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25 km
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37 km
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25 cm
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15 km
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16 km
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18 km
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29 km
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40 km
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65 cm
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16 km
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19 km
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21 km
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32 km
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45 km
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1,5 m
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19 km
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23 km
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24 km
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34 km
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48 km
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Products
VHF-ANTENNA STAND, PACIFIC, PRO-RANGE, ADJUSTABLE
Pacific 6111. Specifications: Description- VHF/Cellular SeaMaster Pro fold down mount; Material- Glass filled nylon - UV inhibited; Weight- 375 g; Height- 106 mm; Base Plate Dimensions- 81 x 63 mm; Hole Centres / Sizes- 61 x 43 mm. Hole diameter: 7 mm; Cable and Plug- 5 m RG58AU with FastFit Jack and FastFit PL259 plug. Use With SeaMaster Pro antennas.
M14600790
VHF-ANTENNA STAND FOR RAILS, PACIFIC, PRO-RANGE
Pacific 6113. Specifications: Description- VHF/Cellular SeaMaster Pro Series rail mount; Material- Glass filled nylon - UV inhibited; Weight- 350 g; Height- 61 mm; Base Plate Dimensions- Designed for use on 1" (25 mm) pipe; Cable and Plug- 5 m RG58AU with FastFit jack and FastFit PL259 plug.
M14600791
VHF-ANTENNA STAND, PACIFIC, PRO-RANGE, FIXED, S/S
Pacific 6166. Specifications: Description- VHF/Cellular LongReach Pro Series; Material: Stainless steel AISI 316; Housing: Acetal; Weight- 300 g; Height- 100 mm; Base Plate Dimensions- 3 x 6 mm holes on diameter 64 mm; Cable- 5 m RG58A/U with Pro Connectors fitted.
M14600795
MARINE STEREO, LTC-PROMARINE 1111BT, BLACK
LTC Promarine Bluetooth Stereo in a round compact size and 100 % waterproof IP67. Fits nicely in with the other instrumentation in the boat. Available in black and white color, both with chrome outer ring. The stereo is at 4 x 65 W MOSFET amplifier. Stereo system has integrated Bluetooth for music streaming directly from your mobile phone (ideal for Spotify). RDS radio with 18 presets and built-in memory back-up so when the power is cut keeps your stereo left the radio memory. Two-row bright display, Low output, USB and AUX input (on the back) and an equalizer with four different settings, and separate bass and treble adjustment. Diameter: 91 mm. Also suitable for bathrooms, saunas and outdoor.
M14600916
MARINE SPEAKER, ULTRA SLIM 30 W
Extra flat and only 25-mm deep IP56 waterproof speaker. Made with the new cutting edge technology allowing to reduce drastically the cable depth while granting an excellent acoustic performance. Front panel diameter: 150 mm, Cone diameter: 127 mm, Depth: 25 mm, Output power: 30 W, Frequency: 100 - 19.000 Hz, Sensibility: 88+- 2 dB.
29.723.01
Special Price: 19.99 €
(Normal Price: 23.75 €)
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