Furuno FELCOM251, Руководство по установке

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2. INSTALLING THE SYSTEM
2-11
FELCOM251 Antenna Unit mast length
The below table shows the values for a FELCOM251 Antenna Unit mast without stays
or wires. Note that these values are only guidelines - always consider the environment
and characteristics of the ship before deciding on the mast dimensions.
The mast mount kit interfaces to a 1.5” tube (OD 48.3 mm – absolute maximum OD
52 mm). Masts with larger diameters must be tapered and the upper part of the tube
(approximately 50 mm) must have a diameter of 1.5”.
Antenna Unit mast length FELCOM251
2.3 Installing the Antenna Unit
Specialized tools to prepare before installation
The following tools are used in the Antenna Unit installation and should be prepared.
2.3.1 Antenna Unit grounding
You may ground the antenna using the mounting bolts.
If the antenna cannot or should not be electrically connected directly to the mounting
surface, you can use a separate grounding cable to make the connection between the
antenna and the common ground to which the Communication Unit is also connected.
For example, you can connect a separate grounding cable when vibration isolators are
used at the mounting bolts (see section 4.9.2).
To obtain a good ground connection, the metal underneath the head of at least one
bolt must be clean of insulating protective coating and a serrated washer should be
used. After tightening the bolts we recommend that you seal the area suitably in order
to avoid corrosion of the grounding point. Use stainless steel bolts and washers.
For further grounding information read chapter 4.
OD(mm)
Wall
Thickness(m
m)
Weight (kg/m)
Inertia
(X10
6
mm
4
)
Max. free mast
length
(steel), m
48.3 3.25 3.61 0.117 < 0.6
48.3 4.05 4.43 0.139
50 3.00 3.48 0.123
60.3 3.65 5.10 0.262 < 0.8
60.3 4.50 6.17 0.309
76.1 3.65 6.80 0.547 < 1.0
76.1 4.50 7.90 0.651
88.9 4.05 8.47 0.974 < 1.1
88.9 4.85 10.10 1.140
Tool Size Used for...
Hex wrench 5 mm FB-1251 installation and/or mast mounting kit.
8 mm FB-1501 installation.