Homing Mode (HOME)

TM 11-5820-670-30

1-60. RADIO SET AN/ARC-131 INTERUNIT CIRCUIT DETAILS. (CONT)

Homing Mode (HOME)

In homing mode, +27.5 vdc primary power is applied as indicated in T/R mode, except that

+ 27.5 vdc is also supplied to the rf control to operate the homing circuits. The homer operate voltage

is coupled from contacts 9, 10, 11, and 12 of S9105D front to contact 8 of S9105A front.

In HOME mode, contact 8 is connected to contact 7. From contact 7 of S9105A front, the homer oper-

ate voltage is connected through pin DD of control unit connector J9101 and through interconnecting

wiring to pin 16 of receiver-transmitter connector P9601. From there, the homer operate voltage is

connected to pin 12 of the rf control to operate homing relay K4502 which, in turn, activates other

homing circuits.

The homer operate voltage is also applied from contact 7 of S9105A front through R9101, a current

limiter, to pin GG of control unit connector J9101. This voltage is used to operate the homing indicator

flags.

Operation of the flags depends on the ground return. This ground return originates in the receiver-

transmitter and is connected through the audiofrequency amplifier when sufficient signal is received to

cause unsquelching.

The ground is connected, as in RETRAN operation, through pin 5 of the audiofrequency amplifier con-

nector, through pin 10 of receiver-transmitter connector P9601, pin Y of the control unit connector,

and contacts 11 and 12 of S9106 to contact 1 of S9106. From contact 1 of S9106, the ground is con-

nected to contact 9 of S9105B rear, which connects to contact 10. From contact 10 of S9105B, the

ground return is connected to pin FF of control unit connector J9101 and then to the homing indicator

to operate the flags.

The homing indicator horizontal needle is controlled by the signal strength voltage from the homer

assembly. Signal strength voltage is coupled from the receiver-transmitter to pin MM of control unit

connector J9101. From pin MM, signal-strength voltage is connected to contact 6 of S9105B rear.

In HOME mode, contact 6 connects to contact 5. From contact 5, signal strength voltage is coupled

through pin NN of control unit connector J9101 to the homing indicator. The homing indicator

horizontal needle negative terminal is returned to the receiver-transmitter.

The homing indicator vertical needle is controlled by the homer course voltage from the homer assem-

bly. The homer course voltage is coupled from the receiver-transmitter to pin t of control unit connec-

tor J9101. From pint, it is connected through S9105B rear from contact 2 to contact 1.

From contact 1, homer course voltage is connected through pin s of control unit connector J9101 to

the homing indicator vertical needle (+) input. The vertical needle (-) is returned directly to the

receiver-transmitter.

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