Chapter 1. GENERAL INFORMATION - TM-11-5820-815-140013

TO 31R2-2GRC171-2

TM 11-5820-815-14

NAVELEX 0967-LP-544-5010

CHAPTER 1

GENERAL INFORMATION

information from the radio control into servo motor drive

1-1. DESCRIPTION AND PURPOSE.

to position the rf filter in the rf filter module.

1-2. PURPOSE. Radio Set AN/GRC-171, shown in figure

1-10. FREQUENCY SYNTHESIZER MODULE A2. The

1-1, is a uhf receiver-transmitter for air traffic control

frequency synthesizer module contains a phaselocked

communications at collocated vhf/uhf receiver-

loop (p11) and transmit/receive transfer switch that

transmitter sites. The equipment provides AM and wide-

converts frequency select information from the radio

band data communications on any 1 of 7000 channels

control into transmit rf that is transferred to the power

(25-kHz channel spacing) in the 225to 399.975-MHz

amplifier module or receive injection that is transferred to

band. The equipment is completely solid state providing

the receiver rf module.

20-watt AM carrier output.

1-11. RECEIVER RF MODULE A3. The receiver rf

1-3. DESCRIPTION. Radio Set AN/GRC-171 (radio set)

module contains a double conversion uhf receiver that

consists of Radio Receiver-Transmitter RT980/GRC-171

converts receive rf from the rf filter module into receive

(receiver-transmitter), Radio Set Control C-7999/GRC-

audio (or data) to the audio module. The receiver rf

171 (radio control), a cable interface kit, and a slide

module includes a noise channel to blank receive audio

mounting hardware kit.

of impulse type noise.

1-4. The RT-980/GRC-171 consists of nine plug-in

1-12. AUDIO MODULE A4. The audio module contains a

modules (shown in figure 1-2) contained within a

receive audio circuit with squelch, a transmit audio

chassis. The modules are attached to the chassis by

circuit, and a transmitter keying circuit. The audio circuit

captive screws or by a module retaining bracket. All

amplifies and shapes the frequency response of receive

electrical connections to the RT-980/GRC-171 are made

audio (or data) from the receiver rf module and applies

through four connectors mounted on the rear panel of

the audio (or data) to the headset and main audio output

the chassis. Front panel test meter and test points are

(or data output) of the receiver-transmitter. The transmit

provided for maintenance and troubleshooting. The unit

audio circuit amplifies and shapes the frequency

mounts in a standard 482.6-mm (19-in) rack cabinet and

response of input audio (or data) and applies transmit

is cooled by convection. The RT-980/GRC-171 can be

audio (or data) to the modulator of the power amplifier

operated locally with front panel controls or remotely at

module. The transmit keying circuit converts remote

distances up to 45.7 m (150 ft) with Radio Set Control

push-to-talk keying into transmit key lines.

C-7999/GRC-171.

1-13. DC-DC CONVERTER MODULE A5. The dc-dc

1-5. The cable interface kit contains a 1.83-m (6-ft) 120-

converter module contains a regulating dc-dc converter

V ac power cord and all multiple pin mating connectors

and a nonregulating dc-dc converter. The regulating dc-

for the RT-980/GRC-171 and C-7999/ GRC-171. All

dc converter converts unregulated dc from the

interconnecting wiring except the 120-V ac power cord is

transformer/rectifier circuit on the chassis into regulated

supplied by the user.

+26 V dc. The nonregulating dc-dc converter converts

+26 V dc into unregulated voltages to the voltage

1-6. The slide mounting hardware kit contains the

regulator module.

cabinet slides, brackets, and hardware required to mount

the RT-80/GRC-171 in a standard 482.6-mm (19-in) rack

1-14. VOLTAGE REGULATOR MODULE A6. The

cabinet. Slide rails are attached to the RT-980/GRC-171

voltage regulator module converts unregulated voltages

at the factory.

to power circuits of the receiver-transmitter and radio

control.

1-7. Radio Set Control C-7999/GRC-171 contains

controls for remote frequency select, power on-off,

1-15. RF FILTER MODULE A7. The rf filter module

squelch on-off, and receive audio level control.

contains a transmit/receive switch, tunable rf filter, and

directional coupler that transfers and filters transmit rf

1-8. DESCRIPTION OF MODULES.

from the power amplifier module to the antenna or

receive rf from the antenna to the receiver rf module.

1-9. D/A SERVO AMPLIFIER MODULE Al. The d/a

servo amplifier contains a digital-to-analog converter and

servo amplifier that converts frequency select

1-1