98-175666-A
Appendix E: Grounding and RF protection
E-4
Grounding Recommendations
To ground the ADU
Terminal grounded at the hull (recommended)
In this case the ADU is grounded to the ship via one (or more) of its mounting bolts. Make
sure to remove painting, dirt, grease etc. at the mounting holes in order to make good
electrical contact to the hull. Use serrated washers when securing the mounting bolts and
seal the joint with protective coating to avoid corrosion.
Terminal grounded at a dedicated RF ground (alternative)
In this case the ADU is grounded with a separate ground cable. The ground cable must be
routed parallel and close to the shielded coax cable connecting the ADU to the BDU
grounding kit. A heavy gauge wire with tinned strands (min. 6 mm
2
) can be used for this
purpose.
E.2.4 Alternative grounding for aluminum hulls
The following guidelines assume a two-wire, isolated grounding arrangement; that is no part
of the circuit, in particular the battery negative, is connected to any ground potential or
equipment.
Note
For optimum grounding use the mounting bolt located closest
to the ADU cable plate, see
Note
The ADU must be electrically isolated at its mounting bolts by
means of shoulder bushings and washers ensuring the isolated
RF ground - see
Isolation of the ADU from the mounting base
Figure E-3: Grounding at a dedicated RF ground (alternative)
Antenna grounded
with separate cable
Antenna
Mast
(electrically bonded
to the steel hull)
Base Plate
(Antenna isolated
from the the hull)
Antenna grounded
with mounting bolts
Antenna
Mast
(electrically bonded
to the steel hull)
Base Plate
(electrically bonded to
the hull though the mast)
Recommended
Alternative
