Furuno Felcom 250 Service Manual page 332

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;
FB-1500 (Class 8) : 12 to 22.0 dBW (+1/-2 dB)
FB-1250 (Class 9) : 5.1 to 15.1 dBW (+1/-2 dB) Controlling 1 dB step
Radome
loss
RX 0.1 dB
FB-1500
TX 0.1 dB
RX 0.1 dB
FB-1250
TX 0.1 dB
Note)
- As for the receiving output level, when the receiving input level into the
Antenna is -113.0 dBW/m
-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
Antenna Duplexer
gain loss
17.6 dBi 0.7 dB
18.2 dBi 0.7 dB
11.6dBi 0.7dB
12.4dBi 0.7dB
2
to -143.0 dBW/m
11-17
11.2 Antenna Unit: FB-1500/1250
Controlling 1 dB step
Table 11.2.2 Antenna gain distribution
LNA HPA
Cable loss Output
gain output
38.8 dB
5.4 dBW
38.8dB
4.4dBW
2
, the Antenna output level will be
Note)
- 79.4 to
0.2 dB
- 49.4 dBm
0.2 dB 22 dBW
- 75.6 to
0.4dB
- 55.6 dBm
0.6dB 15.1 dBW