Furuno FAR-3220W-BB, Installation Manual

Page: 58 / 185

2. WIRING
2-22
4. Pass the LAN cable through two locking wire saddles and connect it to port J821.
Attach a crimp-on lug to the shield of each cable, referring to the figure below for
the type of crimp-on lug to use. Connect shields to the locations shown below.
Bind all cables with the locking wire saddle and two cable ties (local supply).
5. Check that armor of cables are lying in their respective cable slots then fasten the
cable clamp.
Flexible waveguide (FR-9)
The RF interconnection between the antenna unit and the transceiver can be made
with a flexible waveguide (FR-9). If the rectangular waveguide is used, observe the fol-
lowing installation guidelines.
• Correctly installed waveguide runs ensure the most efficient transmission of electri-
cal energy at high frequencies. Electrical losses, however, occur in the waveguide
runs. To minimize them the following factors are of great importance: minimum
length, airtightness and electrical continuity.
• Another consideration required is that of frequency disturbance. The transmitting
valve, a magnetron, is the primary oscillator in the radar. This is different from the
oscillation system at lower frequencies in which conventional radio valves are used.
In the latter case, the primary oscillator is always protected from the effects of load
impedance by a buffer stage so that frequency and waveform are left unobstructed.
With a waveguide and magnetron, however, mismatch of impedance causes “fre-
quency pulling.” For this reason, the number of possible mismatches in a waveguide
run, i.e., joins and bends, must be kept minimum.
• Each pair of flanges should be coupled with one O-ring, four bolts and spring wash-
ers and the choke flange must be in the upper position. The bolts and O-ring must
be greased before insertion to facilitate removal if required at a later date.
Connect shield of
LAN cable here.
Bind all cables
with two
cable ties
(local supply).
Connect shield of antenna cable, serial
cable and sub monitor cable here.
Pass LAN cable
through these
locking wire
saddles.
Connect LAN cable
to port J821.
Bind all cables
with locking wire
saddle.
Cable and crimp-on lug to use for shield:
Antenna cable:
FV2-3 BLU
LAN cable: FV2-M3 BLU
Serial cable: FV1.25-3(LF) RED
Sub monitor cable: FV5.5-4(LF) YEL