Sea Tel 5012-91, Installation Manual, Page: 26 / 138

5012-91 Installation Manual Installation
3-6
20. Two cables may be passed through each of the
Roxtec® Multidiameter® CM-20w40 blocks
provided.
21. If cables larger than 1.65cm/0.65in outer diameter
will be used, larger single-cable Roxtec®
Multidiameter CM-40 10-32 blocks are available to
allow three cables of up to3.25cm/1.28in diameter
to be used. The
rubber bar and the three double-
cable Roxtec® Multidiameter blocks will be
replaced by the three larger Roxtec®
Multidiameter blocks
.
HINT: It may be helpful to put the clamp bar and
rubber bar in place (held loosely by one screw) to
hold some of the Roxtec® Multidiameter blocks in
place while you complete the others.
22. Re-install the clamp bar using the hardware removed
in step 14 above.
23. Remove the tag lines.
24. Remove the lifting sling.
25. Remove the four lifting eye nuts and re-install the
original perimeter bolt hardware (the eyes are
galvanized with bare thread that will rust if left
exposed to the weather). Save the lifting eye
hardware in case lifting of the ADE is required in the
future.
3.4. Grounding the Pedestal
The antenna pedestal must be grounded to the hull of the ship. A grounding point is provided on the upper base plate
to ground the pedestal. A ground wire, of appropriate gauge for it’s length, must be provided to ground the pedestal to
the mounting platform that it will be bolted to (this is usually on or near the mounting surface). This mounting must
also be electrically common with the hull of the vessel.
If a longer ground connection is required to reach a common metal connection to the hull, you must provide that
longer cable/strap that is of sufficient gauge and length to ground the pedestal to the nearest grounding point of the
hull.
Solid strap
is the conductor of choice for low impedance RF ground connections because the RF currents tend to
flow along the outer surface and the strap has a large smooth surface area to take full advantage of this effect.
Braid is the conductor of choice where flexibility is required. Sea Tel uses braid to cross axes of the antenna pedestal
and to connect various subassemblies together.
Wire
is the easiest to install and connect and is readily available with a weather protective jacket. 4 awg and 6 awg
bare solid copper wire is commonly used as safety grounds and very basic lightning protection grounds. 2 awg
stranded wire is often used for lightning grounding and bonding and it much more flexible.