Installing The Antenna Unit - Furuno Inmarsat FleetBroadband FELCOM251 Installation Manual

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".
OD(mm)
48.3
48.3
50
60.3
60.3
76.1
76.1
88.9
88.9
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.
Tool
Hex wrench
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.
Antenna Unit mast length FELCOM251
Wall
Thickness(m Weight (kg/m)
m)
3.25 3.61
4.05 4.43
3.00 3.48
3.65 5.10
4.50 6.17
3.65 6.80
4.50 7.90
4.05 8.47
4.85 10.10
Size
5 mm FB-1251 installation and/or mast mounting kit.
8 mm FB-1501 installation.
2. INSTALLING THE SYSTEM
Max. free mast
Inertia
6 4
(X10 mm )
0.117 < 0.6
0.139
0.123
0.262 < 0.8
0.309
0.547 < 1.0
0.651
0.974 < 1.1
1.140
Used for...
length
(steel), m
2-11