Chapter 2. FUNCTIONING OF EQUIPMENT

TM 11-6625-2609-34

CHAPTER 2

FUNCTIONING

EQUIPMENT

the controlled equipment to a point where the

2-1. Use of Equipment

ground is removed from wires A and C and the

a. Maintenance Kit, Electronic Equipment MK-

operating voltage is removed from the motor,

1 0 0 4 A / A R C (maintenance kit) is a portable

By setting the radio control to the other posi-

equipment used in field testing and adjusting

tions, related two-wire combinations are grounded

Radio Set AN/ARC-134.

in accordance with the standard 2 x 5 frequency-

b. The maintenance kit includes Panel, Test,

selector code shown in figure 2-1.

Electrical SB-3716(P)/ARC (test panel) mounted

c. B, figure 2-1, shows a system for controlling

on the front of the equipment. The test panel

an equipment having 100 channels, Since two

h o u s e s Control, Radio Set C-7197/ARC-134

controlled digits comprise any one frequency

(radio control) ; Intercommunication Control Set

channel, two switches are required in both the

C1611D/AIC; various input and output jacks;

radio control and the controlled equipment. Two

and switches, indicators, meters, and controls that

g r o u p s of five control wires interconnect the

are used to check and adjust for proper operation

switches, To simplify the explanation, the 100

of the AN/ARC134.

channels have been assigned frequencies from

c. The intercommunication control set is used

100 to 199 MHz, with l-MHz spacing between

to verify proper performance of the intercom-

channels. Switch S1 is the l-MHz selector and

munication control set in the vhf communications

switch S2 is the 10-MHZ selector. The radio con-

network under test.

trol is shown set to 112 MHz. Of the five-wire

group interconnecting switch S1 in the radio con-

d. The radio control is used to provide power

trol and switch S1 in the controlled equipment,

control, receiver volume control, and channel se-

wires A and C are grounded, representing the

lection for the AN/ARC-134 under test. A COMM

digit 2 (2 MHz). Wires A and B, representing the

T E S T switch on the radio control provides a

digit 1 (1 MHz), are grounded in the five-wire

means of checking the operation of the AN/ARC

group interconnecting switch S2 in the radio con-

134 with the receiver squelch circuit disabled.

trol and switch S2 in the controlled equipment.

T h e tuning motor is driven until the ground

2-2. Basic Two-Out-Of-Five Frequency-

is removed from wires A and C of S1 and A and

Selection System

B of S2. The gearing between the tuning motor

a. The two-out-of-five (2 x 5) frequency-selec-

and the switches in the controlled equipment is

tion system requires five control wires for each

such that switch S1 (the l-MHz switch) makes 10

controlled digit in a channel frequency. Frequen-

revolutions for each complete revolution of switch

cies are selected by simultaneously grounding two

S2. This provides 100 different points (channels)

wires out of each five-wire group. A, figure 21,

at which the tuning motor may be stopped.

shows a simplified system for controlling an equip-

d. Solid-state frequency-selection circuitry that

ment having only 10 channels. Since each channel

uses the 2 x 5 selection system can be used in the

may be represented by a single digit, only one

controlled equipment, either in place of, or in

group of five control wires is required.

combination with, the motor-driven arrangement

b. For example, when the radio control is set

(fig. 2-1 ). In any case, a group of five wires is

to position 2 (A, fig, 21 ) control wires A and C

required for each controlled digit, with selection

are grounded. The tuning motor then drives the

being accomplished by grounding two of the five

switches and the frequency-selecting circuits in

wires.

2-1