Furuno FS-1503 - Manual (Page 14)

1-7
1.4 Mounting of Antenna
About antennas
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.
There are various types of SSB 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 6 to 15 meters. 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.
A long wire antenna is inexpensive and in general provides better performance than a whip
antenna, provided the vertical part is long enough.
A whip antenna is easier than a long wire antenna to install and provides good overall coverage
of most SSB frequencies. In fact, if you don’t plan to venture more than 500 miles from shore
and the ground system is excellent, a simple 7 m (23 feet) whip antenna will probably suffice.
A whip is installed as high as possible (though height is not so critical as with VHF since SSB
is frequency dependent, not range dependent), away from any nearby objects.
Mounting considerations
When selecting a mounting location, keep the following points in mind:
• The length of the vertical portion should be longer than 4 meters, and the slant angle of that
part should be within 10 degrees of vertical.
• Separate the antenna as far away as possible from stays, metallic objects, direction finder
antenna, Inmarsat antenna.
• Locate the insulator away from funnels and masts.
• If the antenna coupler is installed outdoors, use a lead-in insulator 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.