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Military

Chapter 5

Wire and Cable Operations

5-1. General

a. Wire and cable are used to interconnect activities within CPs and between radio relay terminals and switching centers. Long haul wire circuits (trunks) are installed to complement radio systems when time, personnel, and equipment are available. Wire is especially useful in operations where movement is limited.

b. Summarized below are some of the advantages and disadvantages of using wire and cable.

(1) Advantages.

(a) Reduces the need for radio and decreases radio interference.

(b) Reduces the electronic signature of CPs.

(c) Reduces the enemy's jamming, interference, and direction-finding capabilities.

(d) Provides backup and increased traffic-passing capabilities for radio systems.

(e) Is not subject to interference or jamming.

(f) Can be secured by VINSON or PARKHILL COMSEC equipment and wire line adapters.

(2) Disadvantages.

(a) Slow to install/recover. Requires additional manpower.

(b) Not a secure means unless encrypted. Wire has some security but is subject to disruption.

(c) Not reactive to fast-moving situations.

(d) Limited by terrain and distance considerations.

(e) Susceptible to damage by friendly action; for example, wheeled and tracked vehicle movement.

(f) Susceptible to damage by indirect fire.

(g) Is a good conductor of EMP which will damage attached telephone and switching equipment.

5-2. Installation Considerations

One of the first actions when establishing a signal site is the start of intra-site wire/cable installation. Practically all signal equipment at some point interfaces with wire/cable, especially when there is a shortage of multichannel equipment. The following actions are essential for successful wire/cable installation:

a. Plan for and requisition sufficient quantities of wire/cable and installation equipment to provide for known and recurring requirements. The range of field wire circuits varies with the type of wire and the terminating equipment. For planning purposes, the range of field wire circuits using battery operated telephones is 22.5 to 35.4 km (14 to 22 miles); using sound powered telephones, it is 6.4 km (4 miles).

b. Cross train personnel on wire/cable installation and operations. Personnel associated with equipment in short supply, and personnel in staff sections, should be cross trained so they will be capable of installing wire/cable circuits for their element/headquarters. Then each section that requires a telephone line can lay its own field wire to a centrally located, premarked distribution box J-1077A/U.

c. Plan for and install pre-positioned wire termination sites to the maximum extent possible. This pre-positioning should be related to planned or potential operations in order to provide headquarters elements immediate connection to the division/corps wire system upon displacement. This assumes that the potential site is in friendly territory and that operations in the area will not destroy the system. Typical uses of pre-positioned wire systems include quick connection of a brigade or tactical CP element or of a retransmission/NRI station to the system.

d. Fabricate short runs using WD-1 field wire when multiple-pair cables are in short supply. Use special caution to tag and identify pairs when using this technique.

e. Plan for additional vehicle, fuel, and maintenance support needed for IOM of wire and cable systems. Within most signal TOEs, the volume of cable and wire authorized exceeds the unit's capabilities to transport it in a single movement.

5-3. Equipment Utilization

a. The following wire and cable are used predominantly throughout the tactical arena:

(1) WD-1/TT consists of two 23-gauge conductors, individually insulated and twisted together.

(2) WD-lA/TT has two insulated conductors bonded together.

(3) WD-36/TT is a two-conductor, lightweight assault wire. It is used when rapid installation and light weight are factors of primary importance. It is designed for one-time use only.

(4) WF-16/TT is a four-conductor (two-pair) field wire that is used with the new 4-wire telephone system.

(5) WF-8( )/G, spiral-four cable, is a 4-wire transmission line for carrier communications systems. It is used for long distance VF circuits. A universal connector plug is attached to each end.

(6) CX-11230G is an interarea coaxial cable. It consists of two twisted coax tubes and provides transmission lines for 12-, 24-, 48-, and 96-channel TDM/PCM systems.

(7) CX-4566 is an intersite, multi-pair cable. It consists of 26-pair and is used for internal site connections and limited distance extensions to CPs.

b. Additional equipment is available to combat distortion and loss on long cable runs. TD-204 telephone repeaters are used to increase the strength of a signal that has been decreased by line loss. It consists of amplifiers and associated components (repeating coils, equalizer networks, and hybrid coils). TD-206B/G pulse form restorers retime and regenerate a pulse train on a PCM cable. The pulse form restorers are placed at one mile intervals up to a total of 39 restorers on a given cable run, for a total maximum of 64.4 km (40 miles). The maximum channel capability of the PCM cable run is 48 channels. The TD-202 in addition to TD-204 and TD-206B/G are used by AN/TRC-117, AN/TRC-110, AN/TCC-60/69, AN/TCC-61, and AN/TCC-65.

c. Fiber-optic cable has become an integral part of the Army inventory. It is available for use in the tactical environment. Fifteen-channel, fiber-optic cable will provide full duplex digital communications over a maximum range of 6 to 8 km (3.8 to 5 miles) with an average distance estimated to be 4 km (2.5 miles) (without restorers) at a data rate of 72 kilobits. With restorers, range, and rate increase up to 19.2 megabits and up to 64.4 km (40 miles).

5-4. Installation Methods

a. Aerial (overhead) wire/cable provides the most satisfactory service and is the easiest to maintain. However, it is subject to weather, enemy action, EMP, and artillery airbursts, and requires more time to install.

b. Surface wire/cable requires minimum time and equipment to install. Installed properly, it provides reliable circuits; installed improperly, it requires immediate and constant maintenance. It is also vulnerable to damage by troop, vehicular movement, and weather.

c. Buried wire/cable is more electrically stable than surface or aerial installation, and is less subject to weather. It is the preferred installation if time permits. It is difficult to maintain and recover. Buried cable also provides better protection from the effects of EMP in a nuclear environment.

5-5. Existing Wire/Cable Systems

Evaluation of available commercial cables may be done in peacetime for contingency use in war. Examples of systems that can offer alternative means are highway telephones, railway systems, and forestry services.

 



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