INMARSAT ANTENNA FEEDS

Seavey Engineering offers antenna feeds for installation in parabolic reflectors used to access INMARSAT satellites. These satellites have revolutionized ship-to-shore communications. They permit voice, facsimile, and data services to be easily implemented even on small vessels. In addition, the extremely reliable nature of these systems has resulted in modernizing emergency messaging in distress situations.

The following antenna feeds are used in INMARSAT Standard "A" terminals, which include those aboard ships (Ship Earth Stations) and those with portable features.

All antenna feeds operate over the frequency band of 1525 - 1559 MHz (receive) and 1626.5 - 1660.5 MHz (transmit). All antennas are right-hand circular polarized. Except where noted, all feeds have SMA jack connectors.

RF power handling capability is 100W and maximum axial ratio is 2 dB. In an accurate reflector, feeds result in sidelobe envelopes meeting the INMARSAT specifications for Standard "A" terminals.

For information on complete INMARSAT antennas, please refer to pages 14 through 17.

SPECIFICATION
Model
Number		 Style Reflector
Diameter (Inches)		 Focal Length
Inches 		Features
8231-800
1
30.0, minimum
-----
 Flat square mounting base, SMA Jack
8231-805
1
30.0, minimum
-----
 Includes 4 -strut adaptor plate, SMA Jack
9112-800
1
30.0, minimum
-----
 Include 3-strut adaptor plate, N Jack
8878-800
1
30.0, minimum
-----
 Dual circular polarization, (2) N Jack connectors. 6.5-inch diameter, 6.6 inches long, 1 dB axial ratio, F/D 0.30 - 0.35
8503-800
2
33.0
15.75
 SMA Jack connector
8512-801
2
33.0
12.50
 SMA Jack connector
8607-515
2
36.0
12.50
 N Jack connector
9326-800
2
40.0
15.75
 SMA Jack connector
9390-801
2
48.0
18.00
 SMA Jack connector
pg103a
Model 8231-800
pg103b
Model 8231-805

pg103d


Model 8878-800

pg103c

Model 8512-801

Model 9820-800 - L-band (1.525 - 1.559 GHz) LHCP Patch Feed
This simple feed system is mounted to the vertex of a large C-band Cassegrain subreflector to downlink INMARSAT signals. It is 6.25 inches diameter and 1/4 inch thick and does not degrade the C-band performance.

pg107f
Model 9820-800