C-Nav 1000 R4, Руководство по установке

Страница: 24 / 82

MOUNTING Page 18
The MGA-2 and MGL-4 uses a 1-14-UNS thread for mounting. Mount the
antenna on a standard US 1” 14 thread pipe or other standard antenna mount
(not included).
Note: Antennas threaded onto a mount should be tightened only by
hand.
Do not tighten the antenna by turning on the antenna cover, instead
hold the mounting shaft located at the bottom of the antenna and tighten by
hand. Do not thread the shaft deeper than ¾. Do not use tools to install the
antenna on the shaft as this may cause damage. Damage caused by over
tightening is not covered by warranty.
Note: Once the system has been correctly mounted and connected, it is
possible to monitor the R4 Navigation Sensor receiving performance via the
graphical interface of the R4 Display. This information can be used to locate
the optimum placement of the antenna. This is further described in section
6.7.
4.3.2 Cabling
The maximum allowable cable loss is 18 dB for the MGA-2 and MGL-4
antennas. The maximum cable length depends on the attenuation the cable
and the chosen antenna. As an aid to cable selection, refer to Appendix
[A.6].
Double shielded coaxial cable is recommended. The coaxial cable should be
routed directly between the antenna and the R4 Navigation Sensor in order
to reduce electromagnetic interference effects. The cable should not be
installed close to high-power lines, such as radar or radio-transmitter lines
or any AIS VHF antenna cable. A separation of one meter or more is
recommended to avoid interference due to RF-coupling. Crossing of
antenna cables should be done at 90 degrees to minimize magnetic field
coupling.
4.3.3 Cable Mounting
Coaxial cables should be installed in separate signal cable channels/tubes
and at least 10 cm away from power supply cables. Crossing of cables
should be done at right angles (90°).
Coaxial cables should not be exposed to sharp bends, which may lead to a
change of the characteristic impedance of the cable. The minimum bending
radius should be 5 times the cable's diameter.
All outdoor installed connectors should be weatherproofed, e.g. with shrink
tubing, watertight seal tape or butyl rubber tape and plastic tape sealing, to
protect against water penetration into the antenna cable.
Secure the cable properly, near the cable ends.
Connect the antenna to the R4 Navigation Sensor before you apply power to
it.
4.3.4 Grounding
The MGA-2 and MGL-4 antennas do not require any antenna ground
connection.