Antenna - Raymarine Ray218 Owner's Handbook Manual

Chapter 2: Installation 25

Antenna

Raymarine recommends that you install a VHF Marine band antenna with a
minimum height of 8 ft. and gain of at least 6 dB.
The coaxial VHF antenna cable connects to the Ray218/Ray55 antenna jack on
the rear panel using a PL-259 VHF type connector. The antenna cable length can
be critical to performance. If you are uncertain, contact a professional installer or
call Raymarine Product Support. If a longer cable length is required, RG-8x (50
ohm) marine coaxial cable or equivalent cable can be used for runs up to a
maximum of 50 feet. If the distance required is even greater, Raymarine
recommends using low loss RG-213 or equivalent cable for the entire run to avoid
excessive losses in power output.
If the antenna RF connector is likely to be exposed to the marine environment, a
protective coating of silicon grease (Dow Corning DC-4 or similar) can be applied
to the connector before connecting it to the radio. Any other extensions or
adapters in the cable run should also be protected by grease and then wrapped
with a waterproofing tape.
Antenna Mounting Suggestions
Mounting the VHF antenna properly is very important because it will directly
affect the performance of your VHF radio. Use a VHF antenna designed for marine
vessels. Since VHF transmission is essentially line-of-sight, mount the antenna at
a location on the vessel that is free of obstruction to obtain maximum range.
If you must extend the length of the coaxial cable between the antenna and the
radio, use a coaxial cable designed for the least amount of power loss over the
entire cable length.
For optimal radio performance and minimal human exposure to radio frequency
electromagnetic energy, make sure the antenna is:
• mounted as high as possible, but at least located at least 1.5 meters (5 feet)
from the radio
• connected to the radio before transmitting
WARNING: Antenna Mounting and EME Exposure
Ensure that the antenna is mounted so that no one can enter the
maximum permissible exposure radius for RF radiation. See the
Safety Notice entitled "Antenna Mounting and EME Exposure" on
page 12.