(3) Satellite acquisition is effected by an
6-3. Terminal/User Interface
openloop scan through the area of uncertainty while
a. The AN/TSC-86 terminal accepts user
observing the carrier level on the antenna control (or
voice/data/TTY traffic for processing and transmission on
remote control). This is normally accomplished with the
a full duplex basis. Individual user lines enter the
receiver tuned to the beacon signal and by manually
terminal through three weatherproof entry panels located
controlling the antenna scan. (A remote antenna control
on the curb side of the shelter. These dedicated entry
box with a signal level meter and drive switches provides
acquisition or tracking capabilities from outside the
shelter.) A threshold circuit automatically stops the
(2) Data entry.
acquisition scan when the signal strength exceeds a set
level. After acquisition, the tracking loop is closed and
b. Multiple RF carrier operation is available using
the antenna periodically scans through a random pattern
four upconverters and associated amplifier/mixer, and
about each axis.
four downconverters. This includes the capability of
interfacing auxiliary IF signals of 70 20 MHz or 700
receiver with the servo system. The antenna control,
track patch panel and downconverter combination
receiver downconverters on a full duplex basis.
permits the option of satellite tracking by means of the
6-4. Terminal Subsystems.
satellite beacon signal or a communications channel
Functionally, the terminal is divided into a radio
signal. A communication tracking module located within
subsystem (RSS), a communications subsystem (CSS),
the antenna control unit accepts a beacon or
and a power pallet. Each of these is briefly described in
the following paragraphs.
downconverter through the track patch panel for
6-5. Radio Subsystem
conversion into antenna tracking drive signals. Tracking
The radio subsystem (RSS) consists of the antenna
by beacon or communications signal is determined by
group and the equipment that receives SHF satellite
selection of the proper signal patch originating at the
signals and converts them to either 70 - MHz IF signals
track patch panel. This patching and the resetting of the
for processing by baseband equipment or 700 - MHz IF
signals for direct routing to users, and converts 70 - MHz
operations needed to make the transfer between these
IF signals from baseband equipment or 700 -MHz
external IF signals to SHF high-ower signals and
b. Receiver Group.
The AN/TSC-86 SHF
transmits them to the satellite. The RSS includes
receiver includes the communications and tracking
antenna tracking controls built in.
signal receiving system composed of an antenna-
(1) The 8 foot antenna group consists of the
downconverters. The two low-noise amplifiers (LNA)
reflector, mounting structure, feed assemblies, low noise
with associated selector switch, wideband preselector,
amplifiers and associated BITE box, drives, and controls.
and BITE assembly are mounted as a subassembly of
The reflector consists of a center section and four
the antenna structure. Signals from the on-line LNA
quarter-section panels (or petals). The antenna contains
enter the shelter and are distributed to the five
both elevation and cross-elevation actuators for driving
downconverters. Antenna tracking via satellite beacon or
the reflector. The actuators are electrically connected by
cables to an antenna control assembly mounted within
All downconverter communications channel
the shelter. A remote control unit may also be connected
output ports terminate at the IF patch panel for routing to
to allow antenna control from outside the shelter.
(2) The antenna system has a limited tracking
(1) Low-noise front end. The low-noise front
motion on each axis of 12.5 degrees. However, sector
end is contained in an antenna-mounted electronics
orientation to any point in space can be accomplished by
(AME) assembly as shown in figure 6-5. It consists of a
initially pointing the front of the antenna structure to the
directional coupler, a wideband filter, a waveguide input
satellite heading and by setting the antenna elevation
transfer switch, two low-noise amplifiers (LNA), and an
between 0 and +90 degrees. Final positioning of the
output coaxial switch (located in the LNA BITE assy).
antenna during its setup is accomplished through the use
The transfer switches select one LNA as the on-line unit
of the antenna linear actuators.
and connect the other to a BITE unit, which contains a
procedure provides the capability for full hemispheric
test oscillator and detector for testing the off-line LNA.
The transfer switches are controlled from the LNA
control/translator inside the shelter. This dual LNA
arrangement provides redundancy.