COBHAM SEA TEL 9711IMA-70, Installation Manual

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Site Survey 9711IMA-70
2-6
2.8.1. ADE/BDE Coaxial Cables
The first concern with the coaxial cables installed between the ADE & BDE is length. This length is used
to determine the loss of the various possible coax, Heliax or fiber-optic cables that might be used. You
should always provide the lowest loss cables to provide the strongest signal level into the satellite
modem.
Signal cable shall be continuous from the connection within the ADE radome, through the structure of
the ship to the BDE. Splices, adapters or dummy connections will degrade the signal level and are
discouraged.
Be careful of sharp bends that kink and damage the cable. Use a proper tubing bender for Heliax bends.
Penetrations in watertight bulkheads are very expensive, single cable, welded penetrations that must be
pressure tested.
Always use good quality connectors that are designed to fit properly on the cables you are using. Poor
quality connectors have higher loss, can allow noise into the cable, are easily damaged or fail
prematurely.
In as much as is possible, don’t lay the coaxes on power cables. Try to have some separation from
Inmarsat & GPS cables that are also passing L-band frequencies or radar cables that may inject pulse
repetition noise –as error bits - into your cables.
2.8.2. Antenna Power Cable
Be cautious of length of the run, for voltage loss issues, and assure that the gauge of the wires is
adequate for the current that is expected to be drawn (plus margin). Antenna power is recommended
(but not required) to be from a UPS, generally the same one that supplies power to the below decks
equipment.
Power cables shall comply with the provisions of IEC 60092-350 and -351 as practical. Power cables
may be routed through the same conduit as the signal cable from the junction box to the base of the
ADE. Power cables shall pass through separate radome penetrations from the signal cable.
The power cable shall be continuous from the UPS (or closest circuit breaker) to the ADE connections
within the radome. The power circuits shall be arranged so that ‘active,’ ‘common’ and ‘neutral’ (ground)
legs are all made or broken simultaneously. All circuit legs shall be carried in the same cable jacket.
2.8.3. Air Conditioner Power Cable
If your system includes a marine air conditioner, run an AC power cable to it from a breaker, preferably
from a different phase of the electrical system than that which supplies power to the ADE & BDE. Be
EXTREMELY cautious of length of the run for voltage loss and gauge of the wires for the current that is
expected to be drawn.
Power cable shall comply with the provisions of IEC 60092-350 and -351 in so far as practicable. Power
cable may be routed through the same conduit as the signal cable from the junction box to the base of
the ADE. Power cables shall pass through separate radome penetrations from the signal cable.
The power cable shall be continuous from the closest circuit breaker to the ADE connections within the
radome. The power circuits shall be arranged so that ‘active,’ ‘common’ and ‘neutral’ (ground) legs are all
made or broken simultaneously. All circuit legs shall be carried in the same cable jacket.
2.8.4. ACU Power Cable/Outlet
The AC power for the ACU and the ADE is not required to be from a UPS (same one that supplies power
to the ADE), but it is recommended.
Power cable shall comply with the provisions of IEC 60092-350 and -351 in so far as practicable.
2.8.5. Gyro Compass Cable
Use good quality shielded cables (twisted pairs, individually foil wrapped, outer foil with braid overall is
best). You only need 2-wire for NMEA signal, 4-wire for Step-By-Step and 5-wire for Synchro … always
use shielded cable. Be cautious of length and gauge of the run for voltage loss issues.
2.9. Grounding
Refer to the Installation chapter for grounding/bonding information.
EAR Controlled - ECCN EAR99