Furuno FELCOM251, Installation Manual, Page: 68 / 122

4. GROUNDING AND RF PROTECTION
4-15
4.9.2 Ground cable – connection
The ground cable must be mounted close to and parallel to the shielded coax cable
thus minimizing ground loop problems. If possible, route the coax cable and the
ground cable in metal conduits bonded to the hull or within a mast (depending on the
actual installation).
The ground cable must be connected at one of the mounting/grounding bolts on the
antenna. Use bolts and washers of stainless steel and seal the joint with protective
coating to avoid corrosion. If the antenna is to be isolated from the mounting base,
shoulder bushings and washers must be used – see section 4.9.3.
In the below drawing, vibration isolators are mounted.
At the other end, connect the ground cable at the Communication Unit grounding kit
as described in section 4.4.1.
4.9.3 Isolation of the Antenna Unit from the mounting base
In cases where the antenna is to be isolated from the mounting base, shoulder bush-
ings and washers (local supply) must be used as illustrated below. Please note that
the isolation has to be implemented on all four mounting bolts (including the bolt se-
curing the ground cable).
Vibration isolator
Plain washer (stainless steel)
Spring washer (stainless steel)
Plain washer (stainless steel)
Serrated washer (stainless steel)
Ground cable
Isolating washer
Isolating shoulder bush
Plain washer
(stainless steel)
Spring washer
(stainless steel)