Nera Inmarsat-c, Service Manual

Page: 25 / 228

2.2 Antenna unit, IC-115
2-5
2.2.2 Antenna element
42 dBm of 1.6 GHz is radiated from the antenna by 14 dBW of EIRP. The receiving
signal of the power flux density, -148 dBW/m
2
to –136 dBW/m
2
of 1.5 GHz is input to
ANT RF receiving circuit with the level of –141 dBm to –129 dBm.
- TX/RX antenna gain: more than 1.3 dBi
(When the antenna elevation angle is +5°.)
- Directional characteristics
Horizontal: Non-directivity
Vertical:
1.3 sin to 1.5 sin (El - 5) dBi
(+5° < El <+90°)
-2.7 cos + 4 cos [4.5 (cos - 5) ] dBi
(-15° < El <+5°)
- Polarization:
Right circular polarization wave
Fig.2.2.2 Antenna element
Fig.2.2.3 shows the vertical directivity diagram at 1.5GHz band.
(Horizontal Directivity: Non-directivity)
Fig. 2.2.3 Vertical directivity diagram
The antenna unit is called “DAISY LOOP ANT antenna”. ANT RF output,
Antenna unit consists of the element, the 3 dB hybrid and the reflector.