Furuno FS-2570 - Manual (Page 18)

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1.5 Antenna
The antenna plays the most important role in radio communication. If it cannot receive or
transmit effectively because of improper installation, even the most sophisticated transceiver will
be rendered useless.
1.5.1 Types of antennas
The most commonly used are a long wire and a whip. Whatever antenna is to be used, the
antenna coupler can tune a long wire or whip whose total length is 7 to 30 meters (23.3 to 100
feet). Although a longer antenna is preferable when the radio is operated only on low
frequencies, use this size of antenna to ensure stable automatic tuning on all bands.
Long wire antenna
A long wire antenna is inexpensive and in general provides better performance than a whip
antenna, provided the vertical part is long enough.
Whip antenna
A whip antenna is easier than a long wire antenna to install and provides good overall coverage
of most SSB frequencies. A whip antenna is installed as high as possible, away from any nearby
objects.
Mounting considerations
When selecting a mounting location;
•
The length of the vertical portion should be longer than 4 meters, and the slant angle of that
part should be within 10 degrees. Separate it as far as possible from:
stays, metallic objects, direction finder antenna, INMARSAT radome antenna
•
Locate the insulator away from funnels and masts.
•
If the antenna coupler is installed outdoors, use a lead-in insulator (Furuno type YA-150 for
FS-1570 or YA-218 for FS-2570) to make the connection. If necessary, use a high quality
antenna switch and stand-off insulator.
•
If the antenna is connected directly to the coupler, use a strain insulator to prevent insulator
fatigue.