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Chptr 4 Multichannel SHF System

Chapter 4

Multichannel SHF System

4-1. System Description

a. Multichannel TACSAT terminals provide a reliable communications system. These terminals provide range extension for the area communications system.

b. The multichannel TACSAT systems use the DSCS II or DSCS III satellite and operate in the 7.25 to 8.4 GHz frequency range. The Army, Air Force, and Marine Corps operate these terminals. The Army and Marine Corps use the AN/TSC-85( )/93( ) while the Air Force uses the AN/TSC-94A/l00A. These terminals are compatible with Tri-Service Tactical Communications (TRI-TAC) and Mobile Subscriber Equipment (MSE) systems. These multichannel TACSAT terminals use FDMA. Therefore, centralized frequency selection and uplink power control are required.

4-2. Deployment

a. Theater through brigade level commanders, special contingencies, and selected divisions use tactical multichannel satellite systems to support Army mission requirements. These systems were developed to augment existing terrestrial multichannel communications systems.

b. Multichannel satellite systems are designed primarily for trunking. Consider these factors when selecting a link requirement for multichannel TACSAT terminals:

c. Consider these factors when deploying the AN/TSC-85( )/93( )s:

d. The AN/TSC-85( ) TACSAT terminal is housed in a modified S-280 shelter. It operates with an organic AS-3036/TSC (8-foot diameter) antenna which is moved in an antenna pallet transit frame (APTF). It may also operate with either the nonorganic AS-3199/TSC (20-foot diameter) antenna or the OE-361(V)/G quick reaction satellite antenna (QRSA). All three antennas operate with DSCS satellites.

e. The AN/TSC-85( ) TACSAT terminal (nodal terminal) provides the following:

f. A modified S-250 shelter houses the AN/TSC-93( ) TACSAT terminal. It operates with the AS-3036/TSC (8-foot diameter) antenna.

g. The AN/TSC-93( ) TACSAT terminal (non-nodal terminal) provides the following:

4-3. Employment

a. Limitations. Channel capacity on DSCS II and DSCS III satellites limits the number of TACSAT terminals that can operate at any one time. This number varies depending on several factors. These factors can include the type of terminal, number of channels, condition of terminals and satellite, size of antenna, and location of terminals within satellite footprint. These factors and others (for example, weather) affect how many terminals can use a satellite. For these reasons it is not possible to give a clear-cut number of terminals that can be operated at any one time. Unfortunately, there is not enough space segment to satisfy all the users. It should be stressed that DSCS II and DSCS III satellites support Army, Navy, Air Force, Marine, and other DOD/non-DOD users. The satellite channels on DSCS II and DSCS III are JCS assets and therefore not dedicated to any particular service.

b. Division.

c. Corps. In the corps, two AN/TSC-85( )s and four AN/TSC-93( )s are pooled to provide support based on the general support (GS) concept. Terminals in support of corps are used for various missions such as restoration of critical links, out of sector operations, and deep operations. This concept has been developed based on the range extension capability of the MSE system. The corps signal brigade installs, operates, and maintains the AN/TSC-85( )/93( )s.

d. Contingency corps.

e. Echelons above corps (EAC).

f. Contingency support.

4-4. Control and Management

a. USARSPACE RSSC GMF managers control and manage the TACSAT communications SHF multichannel terminals. These managers are collocated with the DCA elements at DCA-Europe, DCA-Pacific, and DCA-Washington. The GMF managers are the theater Commander in Chief's (CINC) resource managers and interface to the DSCS and DCA. DCA is the overall DSCS system manager and technical director providing satellite resources to the GMF managers.

b. Communications control matches resources against requirements. It occurs at all levels of the control and management structure. The TACSAT multichannel terminals use the DSCS space system which includes the DSCS II and DSCS III satellites. The availability of resources is considered in all cases as in the single-channel TACSAT program. Emphasis is also placed on mission and organizational priorities in accordance with JCS MOP 178.

c. The process for GMF satellite control, management, and access flow follows the path outlined below.

4-5. System Configuration

a. Capabilities. The AN/TSC-85( )/93( ) terminal configurations allow digital interface with TRI-TAC equipment and MSE. They also provide limited capability for analog input and an ECCM capability for operation in a stressed environment. The Product Improvement Program incorporates replacing the TD-660s, TD-1065s, TD-1069s, KG-27s, and adding the antijam/control modem (AJ/CM), low rate multiplexer (LRM)/TD-1389, and KG-94A. Upon completing the program, the modified terminals will be redesignated as AN/TSC-85B/93B.

b. AN/TSC-85( ). Four TD-660s and TD-1065s will be replaced by four TD-1389s to function as the multichannel multiplexer for unstressed/clear mode communications. Two CV-1548 telephone signal converters and two MX-9635 echo suppressors will be removed and two CV-1548s and MX-9635s will remain. These two unit pairs will remain to support use of two-wire telephones. Four TD-1069s, or their reserved cavity locations, will be removed and replaced by four TD-1389s to function primarily as a multiplexer for the AJ/CM, or alternately as a submultiplexer into another TD-1389. Eight TD-1389s will be installed in each AN/TSC-85( ). Sufficient crosspatch capability will be provided to permit any TD-1389 to function in any role. Baseband patching will be available to provide access to all baseband ports on the shelter entry panels. This will allow the individual channels of the CV-1548/MX-9635 to be patched into any user channel as required. In addition, four KG-27s will be replaced by four KG-94As to provide bulk encryption for four unstressed/clear mode multichannel groups. A nodal terminal AJ/CM will be installed. It will provide an antijamming communications channel and will replace the FM control orderwire. Four STU-III/equivalent 2.4 kbps secure voice devices will be added to provide an AJ/CM stress mode secure voice capability. All other items in the terminal will remain the same.

c. AN/TSC-93( ). Two TD-660s and two TD-1065s will be replaced by one TD-1389 to function as the multichannel multiplexer for unstressed/clear mode traffic. One CV-1548 and one MX-9635 will be removed and one of each will remain to support use of two-wire telephones. One TD-1069, or its reserved location, will be removed and replaced with one TD-1389 to function primarily as a multiplexer for the AJ/CM or alternately as a submultiplexer into another LRM/TD-1389. A total of two LRM/TD-1389s will be installed. Sufficient crosspatch capabilities will be provided to permit any TD-1389 to function in any role. Baseband patching will be able to access all baseband ports on the shelter entry panels. This will allow the individual channels of the CV-1548/MX-9635 to be patched into any user channel as required. In addition, two KG-27s will be replaced by one KG-94A to provide bulk encryption for one unstressed multichannel group. A non-nodal terminal AJ/CM will be installed. This AJ/CM will provide an antijamming communications channel and replace the FM control orderwire. One STU-III/equivalent will be added to the AN/TSC-93( ) to provide an AJ/CM stress mode secure voice capability.

d. Differences. The main differences in tactical multichannel terminal configurations are the types and amount of redundant equipment in the configuration and the terminal's communications capability. The equipment is configured in either a nodal (hub) or non-nodal (spoke) configuration. A nodal terminal can be configured to operate with up to four terminals in a multipoint operation. Any two terminals, either nodal or non-nodal, can be configured to provide a point-to-point requirement.

4-6. Antijamming and ECCM Techniques

a. AJ/CM is a family of spread-spectrum modem equipment designed to provide GMF TACSAT terminals with an ECCM capability for operation in a stressed environment. The normal mode of operation for high capacity links in a benign or nonstressed environment uses the current biphase shift keying/quadraphase shift keying (BPSK/QPSK) modems and FDMA link accesses.

b. The family of modems consists of a network control terminal (NCT), a nodal terminal (NT), and a non-nodal terminal (NNT). The AJ/CM provides a lower capacity 75 bps and 32 kbps communications capability and an antijamming control orderwire.

4-7. Data Entry

Data entry requirements for the operator of a multichannel TACSAT terminal AN/TSC-85( )/93( ) consist of information (data) extracted from the SAA by the CSPE and included in either the mission OPLAN or the exercise OPORD. This information takes the form of--

b. The CSPE extracts this information from the OPLAN/OPORD and provides it to the terminal operator. The data entries are categorized and differentiated between operating parameters, network characteristics, and configuration routines. Figures 4-4 and 4-5 are examples of data entry sheets.