15.4.2 Antenna
Requirements for the antenna
Any good quality antenna that meets the requirements shown below can be used.
Frequency range: 155 to 164 MHz
Impedance: 50 ohms
Polarization: Vertical
Handling power: 30 W or more
Quality: Withstand the marine environment
Installation location
The location and installation of different antennas on a ship is important to ensure
effective communications. Incorrectly installed antennas will degrade performance of
the radio equipment and reduce the range of communications.
Select the location for the antenna considering the following points.
VHF antennas should be placed in a position which is as elevated and free as
possible, with at least 2 meters horizontal separation from constructions made
by conductive materials.
Ideally there should not be more than one antenna on the same level.
The location of mandatory VHF antennas should be given priority compared with
mobile telephone antennas. If they are located on the same level, the distance
between them should be at least 5 meters.
Isolate the antenna from all metallic parts of the ship.
Current will overflow if the antenna touches any metal part of the ship.
Fabricating the Antenna Connector
Step 1 Strip the RG58 cable according to the dimension in the following figure.
Step 2 Put the antenna connector on the cable orderly.
Step 3 Hold the flange between the insulation and the shield.
Step 4 Tighten the nut.
Step 5 Solder the connector and core.
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