Furuno FELCOM 12, Service Manual

Page: 45 / 118

3-5
3.4 Antenna Unit (IC-112)
The transmitting signal from the Communication Unit (1626.5 to 1646.5 MHz) is
supplied to Antenna Unit with an input level of -5 to +10 dBm. The signal is
amplified in the ANT board

a C-class amplifier which amplifies an input of -5
dBm to an output of +43 dBm

, then sent through the diplexer to the antenna. The
transmitting signal is an EIRP of 12 to 16 dBW. The antenna is a Quadrifilar Herix
Antenna and radiates a right circular polarization wave. The antenna gain is 1.5 dBi.
The receiving signal from satellite (1530.0 to 1545.0 MHz) is supplied through the
antenna and diplexer to the ANT board, then amplified 33 to 38 dB, and output to the
Communication Unit.
The isolation between transmitting and receiving signals in the diplexer is more than
40 dB. The insertion loss of the diplexer is less than 1.0 dB.
ATT
ANT element
DIPLEXER
RX : 1530 ~ 1545MHz
TX : 1626.5 ~ 1646.5MHz
ANT (16P0146)
U4
Q9
MRF16030
Q8
MRF16006
Q7
PTB20078
Q6
AT42086
U5
INA10386
FL2
4DFB-1636G-12
-2dB
CR1
HSMP-3894
Q1
ATF10136
Q2 Q14
AT41486 AT42086
FL1
6DFC-1550K-10
12V SW
T/R DET.
12V REG
TX12V
RX12V
T/R CONT
TX28V
TX28V
VR1 : BIAS
VR2 : BIAS VR3 : BIAS
DS1-20R1.637G
C30
Q4/5
2SA1213/2SC2837
U1
µ
PC842G2
U2
AN7812F
+44dBm
-141 ~ -129dBm
RX18V TX29V
TX -5 ~ +10dBm RX -108.5 ~ -91.5dBm
Attenuation : -3 ~ -13dB (1.6G BAND)
•
5D-FB-CV : 30m
•
8D-FB-CV : 50m
•
12D-SFA-CV : 100m
Communication unit
(IC-212)
ANT
RX : -148 ~ -136dB/m 2 (1530 ~ 1545MHz)
TX : 12 ~ 16dBW (1626.5 ~ 1646.5MHz)
TX +8
±
13dBm
RX -120.5 ~ -94.5dBm
+1.5dBi
RX18V TX30V
-1dB
5V REG
U3
AN78L05M
C81 C70 C81
R36-38 75/1W
×
3
Figure 3-4 Block Diagram of Antenna Unit (IC-112)