Appendix A Description Of Optional Equipment; Performance Monitor - Furuno FR-8051 Operator's Manual

Appendix A
DESCRIPTION OF
OPTIONAL EQUIPMENT
This appendix provides a brief description of op-
tional equipment which can be connected to the
FR-8051/8111/8251. For more detailed informa-
tion, see the respective operator's manual.
A.1 Performance Monitor
A performance monitor is required for a radar in-
stalled on vessels of 300 GT and upward engaged
in international voyages. For X-band radars, the
FURUNO PM-30 satisfies the requirement cov-
ering 9410 50 MHz.
The performance monitor is an independent unit,
namely, it is not interconnected with any unit of
the radar system except for the 100 VAC power
cable. In some radars the power cable is not routed
via the power switch or other control of the radar
and the monitor is operated as completely a sepa-
rate device.
Operating a performance monitor
Transmit the radar on the 24 nm range scale and
select a long pulse. The radar screen will show
several arcs, opposite to the heading marker (pro-
vided that the performance monitor is installed
behind the radar antenna as is normally the case.)
If the radar transmitter and receiver are in good
working conditions inasmuch as the original state
when the monitor was tuned, the innermost arc
should appear at 12 nm and there should be a to-
tal of 4 arcs.
The range of the innermost arc reduces 3 nm with
every 3 dB loss of transmitted power. The receiver
sensitivity can be evaluated from the number of
visible arcs; one arc is lost every 3 dB deteriora-
tion of the sensitivity.
Transmitter
performance
Range to Loss
innermost
arc
12 nm 0 dB
9 nm 3 dB
6 nm 6 dB
3 nm or 10 dB
less or none
Display Meaning
TRANSMITTER: normal
RECEIVER: normal
12 nm
TRANSMITTER: 3 db loss
(Transmitter system has lost
half of initial power.
Suspect magnetron and
9 nm
feeder system.)
RECEIVER: normal
TRANSMITTER: 3 db loss
(Transmitter system has lost
half of initial power.
Suspect magnetron and
9 nm
feeder system.)
RECEIVER: 3 db loss
(Receiver has lost half of
normal sensitivity. Suspect
receiver front end, water
leakage in feeder system,
etc.
Receiver
performance
No. of Loss
arcs
4 0 dB
3 3 dB
2 6 dB
1 9 dB
0 12 dB
A – 1