The military has a number of UHF satellites in Geosynchronous orbit (Wiki). When you want to have a 2-way conversation by means of these some amount of gain in the antenna means it needs to be pointed at the satellite. For a portable (man moveable but used in a fixed position) like the LST-5 radio, this is easily done using a simple tripod to support the antenna.
But when you want to use one of the Geosynchronous UHF satellites from a moving vehicle then pointing the antenna at the satellite becomes problematical because it needs to be steered in azimuth. There is no need for elevation steering because a land vehicle can not move far enough to require an elevation change using one tank of fuel. This antenna system is designed to allow a vehicle to keep it's UHF satcom antenna aimed at a given satellite while driving on reasonable level ground.
The antenna mast will have a central Type-N Jack and also a Micro-D connector with 9 sockets.
Photo of just the antenna at: http://www.solarix.net/shack/ Photos below courtesy of Brandon.
Gyroscopic Azimuth Sensor
This BEI QRS11 Gyrochip gyroscopic sensor in mounted inside the antenna positioner box (Fig 5)
The spec for long term drift is 0.2 Deg/sec so in 24 hours it might drift 17 degrees.
The under 100 second drift rate is 0.002 deg/sec so taking 5 seconds to make a right angle turn the drift would be 0.01 degrees.
for UHF Satcom Antenna System
p/n: AV 2095-2
s/n; xx System wt.: 28 lbs.
Trivec-Avanet Corp. FSCM 60188
Hunington Beach, CA 92647, USA
Front Panel Connectors
mil xxxx-10 10 male pins 3-lug, 3/4" O.D., 5 internal key slots
marked Bendix 21-204412-10P 9405 on inside
Has red & black wires and Black & white wires (4 total wires)
Vehicle +24 supply
? Left/Right Up/Down ?
? ? ?
DC Power Cable
Power-Pole connectors in "24 Volt" configuration
Cooner Flex Wire with Silicon insulation
- Circuit Breaker reset 5 Amps
Fig 1 Outside 3/4 view
Cap installed on mast socket
Disk beside mast socket is locating pin
to keep mast from rotating.
Fig 2 Inside Left Plate
Fig 3 top with cap removed
showing the coax rotary joint and
micro D 9 pin connector
Fig 4 Step motor, control board, gyro,
American Precision Ind cmd-50 stepper motor ctrl
The black box mounted behind the front panel is a
Caledex DC/DC Converter 28D5.1000
18 - 54 VDC In
+/-5 VDC Out @ +1100/-900 ma
Fig 5 BEI QRS11 Gyrochip gyroscope
Stepper Motor & Controller
There are signs of corrosion at the bottom of the stepper motor (water got in the box?. . . or ?3206623 ELECTRIC SYNCHRONOUS INDUCTOR MOTOR, Superior Electric Co., Sep 14, 1965, 310/162; 310/49.35; 310/156.64; 310/263
Patent numbers on the motor:
3734254 STEPPING MOTOR WITH AUTOMATIC BRAKE, Sigma Inst. Inc., May 22, 1973, 192/16; 192/223.1; 318/372
3777196 LOW-INERTIA SYNCHRONOUS INDUCTOR MOTOR, Sigma Inst. Inc., Dec 4 1973, 310/156.64; 310/49.32; 310/162
3956650 Laminar-rotor synchronous inductor motor, Sigma Inst. Inc., May 11, 1976, 310/156.65; 310/49.41; 310/162
4025810 Low noise synchronous motors, Sigma Inst. Inc., May 24, 1977, 310/162; 310/156.64
4255696 Synchronous motor system, Sigma Inst. Inc., Mar 10, 1981, 318/696; 310/49.43; 318/400.23 - fractional stepping
American Precision Ind cmd-50 stepper motor Controller box
with sticker: Sold by Servo Systems Co.
To Stepper Motor
Step In: white
5 VDC In: orange
ROI & ROI: resistor
Common Ground: black
+ Voltage Supply: Violet
To Controller PCB
RT-1319 VHF-Hi & UHF Aircraft tranceiver
VRC-83 part of the GRC-206 FAC system