Codan Envoy Reference Manual page 424

I
NSTALLATION
M
OBILE STATIONS
Table 35: Possible faults in the mobile antenna installation (cont.)
Symptom
SWR is bad
Voltage drop in the
fuse, the control
leads, or the battery
Control point
disconnects from
RFU
Related links:
402
Possible cause
The SWR measurement
may have been performed
at the RFU rather than at
the antenna
The antenna may not be
positioned correctly
Faulty coaxial cable or
control cable
The antenna and/or tuner
may not be earthed
correctly
Voltage less than 12 V DC
Inadequate earthing of the
antenna
Earthing the antenna on page 400
Earthing the transceiver in a mobile station on page 397
Action
Ensure the SWR meter is connected to the coaxial
line at the base of the antenna to achieve an
accurate reading.
Check the position of the antenna, ensuring that
the vehicle body is not acting as a shield.
With an SWR meter in place, alter the position of
the antenna to achieve best forward-radiated
power.
Replace faulty cables.
Improve the earth connection.
Check the voltage; it must be greater than
12 V DC on transmit.
Antenna mounting bracket should be welded or
bolted directly to the chassis.
All paint should be cleaned from mating surfaces.
The earth braid provided should be connected to
an independent earthing point going to the
bodywork of the vehicle, or to the battery negative
if possible.
E ™ T
NVOY
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RANSCEIVER EFERENCE ANUAL