Furuno FELCOM 250 Service Manual

 11.2 Antenna Unit: FB-1500/1250
11-17
Fig. 11.2.1 Connecting the Antenna unit and the Communication unit
The L-band transmitting / receiving signals are separated by the Antenna unit IF Module
and the Communication unit IF board Duplexer. The isolation ratio for each filter is 40
dB or more.
The transmitting modulated signals input to the Antenna are π/4 QPSK and 16QAM
signals.
This means that HPA is featured of its linear amplifier, and EIRP control controls the IF
board output level for the Communication unit.
Both FB-1500 and FB-1250 will have the maximum EIRP output when the Antenna
input level is –5 dBm. The EIRP standard for INMARSAT-FB is as follows;
x FB-1500 (Class 8) : 12 to 22.0 dBW (+1/-2 dB) Controlling 1 dB step
x FB-1250 (Class 9) : 5.1 to 15.1 dBW (+1/-2 dB) Controlling 1 dB step
Table 11.2.2 Antenna gain distribution 
Radome
loss
Antenna
gain
Duplexer
loss
LNA
gain
HPA
output
Cable loss Output
Note)
RX 0.1 dB 17.6 dBi 0.7 dB 38.8 dB 0.2 dB
- 79.4 to
- 49.4 dBm
FB-1500
TX 0.1 dB 18.2 dBi 0.7 dB 5.4 dBW 0.2 dB 22 dBW
RX 0.1 dB 11.6dBi 0.7dB 38.8dB 0.4dB
- 75.6 to
- 55.6 dBm
FB-1250
TX 0.1 dB 12.4dBi 0.7dB 4.4dBW 0.6dB 15.1 dBW
Note)
- As for the receiving output level, when the receiving input level into the
Antenna is -113.0 dBW/m
2
to -143.0 dBW/m
2
, the Antenna output level will be
-79.4 to -49.4 dBm.
- The TX output will be the EIRP value for the maximum output power.
42V, 4M ASK, Tx/Rx L band sig.
8D-FB-CV: 30 m/40 m/50 m
12D-SFA-CV: 100 m

Furuno FELCOM 250 Specifications

General

Brand	Furuno
Model	FELCOM 250
Category	Marine GPS System
Language	English