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CHAPTER 1
Radio and RadioTeletypewriter Sets

Section I. Radio Set AN/GRC-106

Installation Procedures

Radio Set AN/GRC-106

Prestart Procedures

Radio Set AN/GRC-106

Starting Procedures

Radio Set AN/GRC-106

Tuning Procedures

Radio Set AN/GRC-106

Stopping Procedures

Section II. Radio Teletypewriter Set AN/VSC-2

Installation Procedures

Radio Teletypewriter Set AN/VSC-2

Prestart Procedures

Radio Teletypewriter Set AN/VSC-2

Starting Procedures

Radio Teletypewriter Set AN/VSC-2

Tuning Procedures

Radio Teletypewriter Set AN/VSC-2

Stopping Procedures

Radio Teletypewriter Set AN/VSC-2

Simplified Installation Procedures Using
TSEC/KW-7

Simplified installation procedures are outlined
below for Radio Teletypewriter Set AN/VSC-2 in a remote configuration when the
set is equipped with AN/UGC-74 communications terminal and TSEC/KW-7 electronic
security encryption device. This procedure assumes that a spare AN/UGC-74, data
cable, and TSEC/KW-7 are not available. If monitoring the radio teletypewriter
set is desired, these items must be furnished separately. If these items are
furnished separately and monitoring is desired, skip step 1
below.

STEP 1. Remove from the RATT set and transport to the
remote site the--

AN/UGC-74.

Data cables.

TSEC/KW-7.

Remote control box.

C-433/GRC remote control unit (P/O AN/GRA-6).

H-33/PT handset.

STEP 2. Required additional items:

AC power cable for AN/UGC-74.

TTY transmit/receive cable (connects KW-7 to remote control
box).

STEP 3. At the local site (RATT set)--

Install batteries in Local Control C-434/GRC (P/O AN/GRA-6) and then
connect Cable Assembly W-1 or W-2 to the AUDIO connector on the AN/VSC-2
control box.

Connect WD-1/TT field wire (pair #l) to the line terminals on the
C-434/GRC.

Connect handset to the AUDIO connector of the C-434/GRC.

Connect WD-1/TT field wire (pair #2) to the remote TTY terminals on the
left side of the AN/VSC-2 control box.

Install a dummy plug on the DUMMY connector located on the left of the
AN/VSC-2 control box.

STEP 4. At the remote site--

Install batteries in the Remote Control Unit C-433/GRC and then connect
WD-1/TT field wire (pair #1) to the line terminals.

Connect the AUDIO cable on the remote control box to the AUDIO connector
of the C-433/GRC.

Connect handset to the AUDIO connector of the remote control box.

Connect WD-1/TT field wire (pair #2) to the TTY binding post of the remote
control box. This is the send/receive line (OWR).

Connect data cable from the AN/UGC-74 to the LOOP IN and LOOP OUT
connectors on the rear of the TSEC/KW-7. Dummy plugs must be connected to the
unused LOOP IN and LOOP OUT connectors to prevent an open circuit.

Connect AC PWR cable to the AN/UGC-74. This cable is not supplied with the
AN/VSC-2.

Connect battery backup cable and battery, if available. (See note 5 on
installation diagram in Figure
1-1.)

Install equipment grounds on AN/UGC-74 and TSEC/KW-7. Good equipment
grounds are essential for operation and safety.

CAUTION

Do not attempt to operate equipment without grounds.

Radio Teletypewriter Set AN/VSC-2

Simplified Installation Procedures Using
TSEC/KG-84A

a. Simplified installation procedures are outlined
below for Radio Teletypewriter Set AN/VSC-2 in a remote configuration when the
set is equipped with AN/UGC-74 communications terminal and TSEC/KG-84A dedicated
loop encryption device (DLED). This procedure assumes that a spare AN/UGC-74,
data cable, and TSEC/KG-84A are not available. If monitoring at the radio
teletypewriter set is desired, these items must be furnished separately. If
these items are furnished separately and monitoring is desired, skip step 1
below.

b. A high level transmit/receive cable for use at the remote site to connect
the J-4024/U and the remote control box is required as an additional item. This
cable is a two-conductor, shielded cable, with a telephone plug (type PJ-055) on
one end and three banana plugs on the opposite end. (See TM
11-5815-616-13, paragraph 2-7, for instructions for fabrication of a
transmit/receive cable if no other cable is available.)

STEP 1. Remove from the RATT set and transport to the
remote location the--

AN/UGC-74.

Data cables.

TSEC/KG-84A (DLED).

J-4024/U interconnecting box.

Remote control box.

AN/GRA-6 control group less the C-434/GRC local control unit.

LS-166/U loudspeaker.

Cable, high level transmit/receive.

STEP 2. At the local site (RATT set)--

Install batteries in Local Control C-434/GRC (P/O AN/GRA-6) and connect
Cable Assembly W-1 or W-2 to the AUDIO connector on the AN/VSC-2 control box.

Connect WD-1/TT field wire (pair #1) to the line terminals on the
C-434/GRC.

Connect handset to the AUDIO connector of the C-434/GRC.

c. Connect WD-1/TT field wire (pair #2) to the remote TYY terminals located
on the left side of the AN/VSC-2 control box.

Install a dummy plug on the DUMMY connector located on the left side of
the AN/VSC-2 control box. If no dummy plug is available, use a short piece of
solid conductor wire as a jumper between pins A and C.

Place the LOCAL REMOTE switch on the control box to the REMOTE position.

DANGER

To prevent the possibility of electrical shock, do this after the OWR line
has been connected et the remote site.

STEP 3. At the remote site--

Install batteries in the Remote Control Unit C433/GRC and then connect
WD-1/TT field wire (pair #1) to the line terminals. This is the audio/keying
line.

Connect the audio cable on the remote control box to the AUDIO connector
of the C-433/GRC.

Connect J-654/G interconnecting box to the AUDIO connector of the remote
control box. Connect the handset and speaker to the J-654/G.

Connect WD-1/TT field wire (pair #2) to the TTY binding post of the remote
control box. This is the send-receive line (OWR).

Connect the transmit/receive cable banana plugs to J-4024/U terminals L1
(send) and L3 (receive). Connect a jumper wire between terminals L2 and L4.
Connect the banana plug that is attached to the shield wire to the ground
terminal.

Connect the transmit/receive cable telephone plug to the remote control
box terminal J1.

Connect DLED power cable (CX-13315/U) from TSEC/KG-84A (J1) to J-4024/U
(J4).

Connect DLED black cable (CX-13317/U) from TSEC/KG-84A (J2) to J-4024/U
(J1).

Connect DLED red cable (CX-13316/U) from TSEC/KG-84A (J3) to J-4024/U
(J2).

Connect data cable (SC-D-960024) from the AN/UGC-74 to the J5 and J7 (TTY
1) connectors on the J-4024/U.

Connect AC power cable to AN/UGC-74. (This cable is not supplied with the
AN/VSC-2. Requisition power cable assembly, 5995-00-271-9444, from TM
11-5815-602-10.)

Connect battery backup cable and battery, if available. (See note 5 on the
installation diagram in Figure
1-2.)

Install equipment grounds on AN/UGC-74, J-4024/U, and TSEC/KG-84A. Good
equipment grounds are essential for operation and safety.

Operational procedures are the same for the AN/VSC-2.

CAUTION

Do not attempt to operate equipment without grounds.

Section III. Radio Teletypewriter Set AN/VSC-3

Operating Instructions

The following procedures cover local AN/VSC-3 operation including the
Intercommunications Set AN/VIC-1(V).

CAUTION 1

Before applying primary power to the AN/VSC-3, start the M577A1 engine or
auxiliary power unit. Failure to do this may cause serious damage to the radio
equipment.

CAUTION 2

When teletypewriter is not transmitting, the auxiliary REC-SEND switch, the
MD-522 (*)/GRC SEND-REC switch, and the remote control REC-SEND switch must be
set to REC to prevent transmitter from being continuously keyed.

Radio Teletypewriter Set AN/VSC-3

Prestart Operating Procedures

Before starting any of the equipment, perform the following procedures:

a. Control Box.

(1) Set main circuit breaker to OFF.

(2) Set inverter circuit breaker to OFF.

b. MX-7778/GRC. Set circuit breakers to OFF.

c. Radio Set AN/GRC-106(*). Set PRIM PWR switch on the AM-3349/GRC-106 to
OFF. Set SERVICE SELECTOR switch on RT-662/GRC or RT-834/GRC to OFF.

d. Radio Teletypewriter Modem MD-522(*)/GRC. Set ON-OFF switch to OFF.

e. Teletypewriter Set TT-98(*)/FG.

(1) Set MOTOR switch to OFF.

(2) Set LIGHT switch to OFF.

(3) Adjust TT-98(*)/FG LINE CURRENT control fully clockwise (for minimum
resistance).

(4) Set LINE SELECTOR switch to 20 MA position.

f. Teletypewriter, Reperforator-Transmitter TT-76(*)/GGC.

(1) Set PWR switch to OFF.

(2) Set MOTOR switch to OFF.

(3) Set LIGHT switch to OFF.

(4) Check the current in the bias circuit by following the instructions in TM
11-5815-238-10.

(5) Open the TT-76(*)/GGC cover and perform the following
procedures if TTY security equipment is to be installed. If not, skip (5), (6), and
(7).

Ensure a 5600-ohm resistor is connected to the power supply and terminal
unit BIAS TEST MA terminals, in place of the shorting strap.

Ensure the SIGNAL/BIAS switch on the power supply and terminal unit is
in the 60 MA position (60 MA is the correct position when using the 5600-ohm
resistor in (a) even though the system is set for 20 MA).

Ensure the plug from the selector magnet cable is in the socket marked
20 MA.

(6) Close the set cover.

(7) Ensure that Device, Low Level Signaling TT523(*)/GGC is
correctly installed on the set behind the transmitter-distributor. Ensure the
plugs are connected and the bracket is secured under the binding post on the
side of the set cover.

Radio Teletypewriter Set AN/VSC-3

Starting Procedures

Start the M577A1 engine or auxiliary power and perform the procedures
below.

a. On the control box, perform the following:

Set the main circuit breakers to ON, and observe that the 27.5 VDC
indicator lights and the DC voltmeter indicates 27.5 VDC.

Set the inverter breaker to ON, and observe that the inverter is
operating.

Set the VOICE-CW/TTY switch to TTY.

If the AN/VSC-3 is to be operated in a NONSECURE mode, set the BLACK-RED
switch to BLACK. If the AN/VSC-3 is to be operated in a SECURE mode, set the
BLACK-RED switch to RED.

Set the LOCAL-REMOTE switch to LOCAL.

b. On the MD-522(*)/GRC, open the control cover to expose additional controls
and complete the following:

Set the ONE-WAY-DUPLEX switch to ONE WAY.

Set the RECEIVE switch to NORM.

Set the METER FUNCTION switch to DC LOOP 1.

Set the DC LOOP 1 switch to 20 MA.

Set the SCOPE INTENSITY control FULLY COUNTERCLOCKWISE.

Set the BFO control to its midscale position.

Set the AUDIO GAIN control FULLY COUNTERCLOCKWISE.

Set the MODE SELECTOR switch to VOICE.

Set the RCV-SEND switch to RCV.

Set the AUTO MARK HOLD switch to ON.

Set the SQUELCH SENS control to the FULLY CLOCKWISE position.

Set the ON-OFF switch to ON.

c. Set the MX-7778/GRC circuit breakers to ON.

d. Set the auxiliary RCV-SEND switch (on the shelf) to RCV.

e. On the TT-98(*)/FG, set the MOTOR switch to ON, LIGHT switch to ON, and
SEND-LOCK switch to SEND.

f. On the TT-76(*)/GGC, set the POWER ON/OFF switch to ON, MOTOR ON/OFF
switch to ON, LIGHT ON/OFF switch to ON, KEYBOARD SEND/LOCK switch to SEND, and
SELECTOR switch to POSITION 1.

g. Send a line of RYs on the TT-98(*)/FG keyboard, and ensure the TT-98(*)/FG
and the TT-76(*)/GGC are printing and perforating tape in response.

h. Send a line of RYs on the TT-76(*)/GGC keyboard. Ensure the TT-76(*)/GGC
is printing and perforating tape, and the TT98(*)/FG is printing in response.

i. Insert a prepunched tape into the TT-76(*)/GGC transmitter-distributor.
Set the transmitter-distributor, and set the transmitter-distributor START-STOP
lever to START. Ensure the TT-76(*)/GGC is printing and perforating tape, and
the TT-98(*)/FG is printing in response. Set the transmitter-distributor
START-STOP lever to STOP.

j. Set the TT-76(*)/GGC SELECTOR switch to position 2. Set the
transmitter-distributor START-STOP switch to START. Ensure the TT-76(*)/GGC is
not printing and perforating, and the TT-98(*)/FG is receiving the tape message.
Ensure the TT-76(*)/GGC keyboard can be used to punch and print local off-line
tape.

k. When using the AN/UGC-74A(V) 3, follow the procedures
listed below.

NOTE: Before operating the AN/UGC-74A(V) 3, the following self test must be
made.

(1) Remove the front cover. Ensure the ON/OFF switch is in
the OFF position.

(2) If a loop back plug (SM-B-91600) is available, disconnect the clock and
data cable from the J1 connector on the rear panel of the AN/UGC-74A(V)3.
Replace the cable with the loop back plug. If the plug is not available, do not
disconnect the clock and data cable from the J1 connector. Place a jumper (using
banana jacks) from the B to the C connectors on the Dummy box. This creates a
loop back circuit to the AN/UGC-74A(V)3.

(3) Release the combination case latches, and extend the terminal out on its
slides until the stop locks engage. (Use caution while doing this because the
cables must go through the case.) The internal controls and switches are
exposed.

(a) Set the internal controls on the interface assembly as follows.

PARITY switch to ODD.

STATE switch to ICT.

REC MOD switch to LO DATA.

XMIT MOD switch to LO DATA.

BAUD RATE switch to 75.

CLOCK INT/EXT switch to INT.

CLOCK +/-switch to +.

FIGURE S/J switch to S.

SIGNAL NRZ/DIO switch to NRZ.

STOP BITS switch to 1.

MODE switch to ASCII.

SELF-TEST switch to ON.

(b) Press the stop locks, and return the terminal to the combination case.
Secure the case latches.

(4) Turn the AN/UGC-74A(V) 3 PWR switch to ON. COPY lamps are on, and all
other lamps are off. The terminal will print the following operational state
message:

SYSTEM INITIALIZED

SWITCH STATE = ICT

OPERATIONAL STATE = ICT

OPERATION CAPACITY = FULL

MODE = ASCII

STOP BITS = 1

BAUD RATE = 75

END OF LINE OPTION = OD OD OA

SPACE OPTION = OFF

LINE LENGTH = 80

LINE FEEDS = 1

RECEIVE ENVELOPE
OPTION = 56 5A 43 5A 43: 4E 4E 4E 4E

TRANSMIT ENVELOPE

OPTION =

56 5A 43 5A 43:4E 4E 4E 4E
7F 7F 7F 7F 7F 7F 7F 7F 7F
7F 7F
7F

PARITY OPTION = ODD

CAPITOL LETTER OPTION = ON

(5) If at any time a test fails, the system will printout a FAIL message and
cite the assembly being tested at the time of the failure. When a test fails
during self test, all testing stops. Notify organizational maintenance.

(6) Perform lamp test by pressing and holding PARITY RESET switch. All
indicator lamps will remain lit as long as the PARITY RESET switch is pressed.

(7) Perform keyboard test by pressing every key on the keyboard. Ensure the
keys do not stick or bind, and the terminal responds properly for every key
depression.

Radio Set AN/GRC-106(*)

Starting and Tuning Procedures

NOTE 1: The AM-3349/GRC-106 HV RESET switch must be in OPERATE position when
the AN/GRC-(*) is turned OFF or ON.

NOTE 2: References to RT-662/GRC apply to RT-834/GRC.

a. Initial preparation for operation.

(1) Ensure the whip antenna is in the operating position, properly connected,
and free of obstructions.

(2) Make sure there are no obstructions blocking the AM3349/GRC-106 air inlet
and outlet vents.

(3) Connect the desired audio accessory (handset, microphone, or telegraph
key) to the control AUDIO connector.

(4) Turn the RT-662/GRC SERVICE SELECTOR switch to OVEN ON. (Allow a minimum
of 10 minutes warm-up time to stabilize equipment.)

(5) Set the RT-662/GRC VOX switch to PUSH-TO-TALK.

(6) Set the RT-662/GRC SQUELCH control to OFF.

(7) Set the NOISE BLANKER switch to OFF. (Used on older RT-662/GRC only.)

(8) Set the RT-662/GRC BFO control to MID-RANGE.

(9) Set the RT-662/GRC MANUAL RF GAIN control FULLY CLOCKWISE.

(10) Set the RT-662/GRC AUDIO GAIN control to MID-RANGE.

(11) Set the RT-662/GRC FREQUENCY VERNIER switch to OFF.

(12) Set the AM-3349/GRC-106 HV RESET switch to OPERATE.

b. AN/GRC-106(*) starting procedure.

(1) Set the RT-662/GRC SERVICE SELECTOR switch to STANDBY and the
AM-3349/GRC-106 PRIM PWR switch to ON, and allow 90 seconds for warm-up of the
AM-3349/GRC-106. Observe that the AM-3349/GRC-106 blowers are energized, and
that the SIGNAL LEVEL METER indicator on the RT-662/GRC will return to the
extreme right portion of the meter scale. (If above indications are abnormal,
refer to Table 2-2, item 1, TM
11-5820-520-20.)

(2) Set the RT-662/GRC SERVICE SELECTOR switch to SSB-NSK (or any operate
mode FSK, AM or CW). SIGNAL LEVEL meter will return to extreme left portion of
meter scale.

(3) Set the AM-3349/GRC-106 TEST METER switch to PRIM VOLT. Observe that the
TEST METER pointer indicates within the area of the two dark green wedges (top
scale) when the SERVICE SELECTOR switch is in the SSBNSK, FSK, AM, or CW
positions. (If above indication is abnormal, refer to Table 2-2, item 2, TM
11-5820-520-20.)

c. Final tuning procedures for AN/GRC-106(*).

(1) Set the RT-662/GRC MHz and kHz controls to assigned
operating frequency. The frequency digits are displayed in the windows directly
above the controls.

(2) Note the AM-3349/GRC-106 ANT TUNE and ANT LOAD predetermined setting on
the antenna tuning and loading chart or the logging chart.

(3) Adjust the AM-3349/GRC-106 ANT TUNE control to match the numbers on the
chart used.

(4) Adjust the AM-3349/GRC-106 ANT LOAD control to match the numbers on the
chart used.

CAUTION

The HV RESET switch should not stay in TUNE position for more than 2 minutes.
If more than 2 minutes are required, move the AM-3349/GRC-106 HV RESET switch to
OPERATE and the RT-662/GRC SERVICE SELECTOR switch to STANDBY for 5 minutes
cooling. After 5 minutes cooling, set the SERVICE SELECTOR switch to the
previous position and the HV RESET switch to TUNE, and proceed with the tuning
procedure. ANT TUNE and ANT LOAD controls will interact with each other. To
center their respective meter pointers, rotate them slowly in the direction
opposite that of the indicated error. Be sure the antenna is attached for proper
loading to prevent damage to the equipment while performing (5) through
(12).

(5) Set the AM-3349/GRC-106 HV RESET switch to TUNE. Wait
for a deflection on the ANT TUNE and ANT LOAD meters.

(6) Adjust the AM-3349/GRC-106 ANT LOAD control for a center scale reading on
the ANT LOAD meter.

(a) Rotate control in the direction the meter pointer is to move. Adjust the
ANT TUNE control for a center scale reading on the ANT TUNE meter.

(b) Rotate control in the direction that the meter pointer is to move,
keeping the ANT LOAD meter as close to center scale as possible.

(c) Tuning of the AM-3349/GRC-106 is complete when simultaneous center scale
readings are obtained on the ANT TUNE and ANT LOAD meters. (If indication is
abnormal, refer to Table 2-2, item 5, TM
11-5820-520-20.) Place the HV RESET switch of the AM-3349/GRC-106 to the
OPERATE position. Place the TEST METER FUNCTION switch of the AM-3349/GRC-106 to
the PRIM VOLT position. Place the HV RESET switch on the AM-3349/GRC-106 to the
TUNE position and observe that the TEST METER pointer indicates within the two
dark green wedges (top scale) of the test meter.

(7) Set the AM-3349/GRC-106 TEST METER switch to LOW VOLT. TEST METER pointer
indicates within green portion of top scale. (For abnormal indication, refer to
Table 2-2, item 3, TM
11-5820-520-20.)

(8) Set the AM-3349/GRC-106 TEST METER switch to HIGH VOLT. TEST METER
pointer indicates within green portion of top scale. (For abnormal indication,
refer to Table 2-2, item 4, TM
11-5820-520-20.)

(9) Set the AM-3349/GRC-106 TEST METER switch to DRIVE CUR. TEST METER
pointer indicates within the two dark green wedges of top scale. (For abnormal
indication, refer to Table 2-2, item 6, TM
11-5820-520-20.)

(10) Set the AM-3349/GRC-106 TEST METER switch to GRID DRIVE. TEST METER
pointer indicates just below (to the left of) gray portion of the bottom scale.
(For abnormal indication, refer to Table 2-2, item 6, TM
11-5820-520-20.)

(11) Set the AM-3349/GRC-106 TEST METER switch to PA CUR. TEST METER pointer
indicates just below (to the left of) the gray portion of the bottom scale. (For
abnormal indication, refer to Table 2-2, item 6, TM
11-5820-520-20.)

(12) Set the AM-3349/GRC-106 TEST METER switch to POWER OUT. TEST METER
pointer indicates just below (to the left of) gray portion of scale. (For
abnormal indication, refer to Table 2-2, item 6, TM
11-5820-520-20.)

CAUTION

The HV RESET switch should not stay in TUNE position for more than 2 minutes.

(13) Turn the AM-3349/GRC-106 HV RESET switch to
OPERATE.

NOTE: ANT TUNE and ANT LOAD counter settings should be logged in the logging
chart with a pencil after (13)
above has been completed. These settings may be used for future tuning
references unless ANT TUNE and ANT LOAD meter pointers indicate in the red (left
or right of center scale) portion of the scale during operation. If the settings
cannot be used, repeat tuning procedures (1) through
(13).

Intercommunications Set AN/VIC-1(V)

Starting Procedures

Turn on and prepare the AN/VIC-1(V) for intercommunication and AN/GRC-106(*)
operation as follows:

Set the AM-1780/VRC POWER CRT BKR ON/OFF switch to ON, and observe that
the POWER indicator lights.

Set the AM-1780/VRC MAIN PWR switch to INT ONLY.

Set the AM-1780/VRC INT ACCENT ON/OFF switch to ON.

Set the AM-1780/VRC RADIO TRANSMISSION switch to CDR + CREW.

Set the AM-1780/VRC INSTALLATION SWITCH to OTHER.

Operate each crew box (C-2298/VRC) on interphone to check AN/VIC-1(V)
system.

Intercommunications Set AN/VIC-1(V)

Local Operation

a. Radio Teletypewriter Reception.

NOTE: MD-522(*)/GRC is provided with an automatic MARK HOLD. With the AUTO
MARK HOLD switch in the ON position, the teletypewriter will not open during the
period of no signals or when signals are too weak for interchangeability.

(1) On the RT-662/GRC, set the SERVICE SELECTOR switch to SSB/NSK or FSK as
required. Set the MANUAL RF GAIN control fully clockwise and the AUDIO GAIN
control at midposition.

(2) Set the MD-522(*)/GRC MODE SELECTOR switch to 850 Hz, 85 Hz, or 85 Hz
DIV, as required.

(3) Set the MD-522(*)/GRC AUDIO GAIN control for a comfortable level of audio
on the incoming tones from the distant station.

(4) Adjust MD-522(*)/GRC BFO control (on 850 Hz only) for two clean ellipses
on the cathode ray tube when a signal having proper speed and shift is being
received.

(5) When signal is received, set TT-98(*)/FG MOTOR ON/OFF switch to ON and/or
set the TT-76(*)/GGC SELECTOR switch to position 1, as desired, to receive
message on the respective teletypewriter. Adjust MD522(*)/GRC BFO control (on
850 Hz only) slightly to eliminate errors in received copy.

b. Radio Teletypewriter Transmission.

(1) Set the RCV-SEND switch on MD-522(*)/GRC to SEND. Set the auxiliary
RCV-SEND switch (on the shelf) to SEND.

(2) Operate the TT-76(*)/GGC or TT-98(*)/FG to send message.

(3) Immediately after sending message, set the auxiliary RCV-SEND switch back
to RCV.

c. Voice or CW Communications.

(1) On the RT-662/GRC, set the SERVICE SELECTOR switch to SSB/NSK or CW as
required. Set MANUAL RF GAIN and AUDIO GAIN controls as cited in a (1).

(2) Set the MD-522(*) GRC MODE SELECTOR to VOICE.

(3) Set the MD-522(*) GRC AUDIO GAIN control for a comfortable level of audio
on the incoming voice or CW signal.

(4) Set the VOICE-CW/TTY switch on the AN/VSC-3 control box to VOICE-CW. Turn
the control box INVERTER switch to OFF.

(5) Observe that the control box NONSECURE VOICE indicator lamp is on.

(6) Operate the controls at the appropriate operator position.

(7) When the AN/GRC-106(*) is to be operated in the CW mode, disconnect cable
W21 from the control box AUDIO connector and connect Telegraph Key KY-116/U to
the connector.

(8) When the AN/GRC-106(*) is to be operated in the VOICE mode without the
AN/VIC-1(V), connect Headset H33/PT or Microphone M-29/U to the control box
AUDIO connector.

Intercommunications Set AN/VIC-1(V)

Stopping Procedures

a. Set PWR switches on the AN/VIC-1(V), MD-522(*)/GRC, TT-76(*)/GGC, and
TT-98(*)/FG to OFF.

b. Set the RT-662/GRC or RT-834/GRC SERVICE SELECTOR switch to STANDBY. Allow
2 minutes for the AN/GRC-106(*) to cool. Keep the HV RESET switch on the
AM-3349/GRC-106 at OPERATE position when AN/GRC-106(*) is turned OFF or ON.
After 2 minutes cooling, set the AM-3349/GRC-106 PRIM PWR switch and the
RT-662/GRC or RT-834/GRC SERVICE SELECTOR switch to OFF.

c. Set the inverter and main circuit breakers on the AN/VSC-3 control box to
OFF.

d. Perform the stopping procedures to shut down.

NOTE: For troubleshooting the VSC-3, see troubleshooting charts on the
AN/GRC-122/142. The only difference is the control box AM-1780.

Radio Teletypewriter Set AN/VSC-3(*)

Cabling Diagrams

Basic operation of the radio teletypewriter set is the same as for the Radio
Teletypewriter Set AN/GRC-142. For detailed instructions on operation, refer to
TM
11-5815-332-15. Figures
1-3 and 1-4
show a cabling diagram for the AN/VSC-3(*).

Section IV. Radio Teletypewriter Set

AN/GRC-122/142

Installation Procedures

Radio Teletypewriter Set AN/GRC-122/142

Major Power Switches

Radio Teletypewriter Set AN/GRC-122/142

Prestart Procedures

Radio Teletypewriter Set AN/GRC-122/142

Starting Procedures

Radio Teletypewriter Set AN/GRC-122/142

Tuning Procedures

Radio Teletypewriter Set AN/GRC-122/142

Operating Communications Terminal AN/UGC-74
(in the ICT state)

Stopping Procedures

Radio Teletypewriter Set AN/GRC-122/142

Troubleshooting

a. Troubleshooting the AN/GRC-122 and the AN/GRC-142 is based on symptoms
that appear during normal operation or during maintenance checks and services.
The troubleshooting chart applies to all models of the AN/GRC-122 and AN/GRC-142
unless otherwise indicated. It assumes the vehicular generating system is in
good working condition. The troubleshooting chart helps the operator localize
the trouble to a particular unit, such as the AN/GRC-106 or the MD-522/GRC. If
the corrective measures do not resolve the trouble, refer to a higher level of
maintenance.

b. If AN/GRC-122/142(*) radio sets are being operated in the SECURE mode and
the problem is believed to be in the security equipment, convert the shelter to
the NONSECURE mode of operation. If the malfunction disappears when the shelter
is converted to the NONSECURE mode, the problem may be in the security
equipment.

c. When operating AN/GRC-122(*) radio sets in DUPLEX mode of operation, turn
off duplex equipment to determine the shelter component related to the problem.

d. All troubleshooting procedures assume the equipment is preset properly and
the radio set is tuned properly. Always check switch positions to ensure the
failure is not caused by improper switch setting. Use signal cabling diagrams to
locate cable connections between components believed to be malfunctioning and to
aid in signal path and equipment interconnections. (See Figure
1-5.)

Radio Teletypewriter Set AN/GRC-122/142
(Plain and C Models)

Power Distribution Panel

Radio Teletypewriter Set AN/GRC-122/142
(A, B, and E Models)

Power Distribution Panel

OWR or DX Inverters

Shelter

Operation

Section V. Radio Set AN/GRC-26D

Installation Procedures

Radio Set AN/GRC-26D

Prestart Procedures

Radio Set AN/GRC-26D

Starting and Preset Procedures

Radio Set AN/GRC-26D

Tuning Procedures

Radio Set AN/GRC-26D

Stopping Procedures

Section VI. Radio Teletypewriter Set AN/GRC-46

Installation Procedures

Radio Teletypewriter Set AN/GRC-46

Preoperational Procedures

Radio Teletypewriter Set AN/GRC-46

Prestart Procedures

Radio Teletypewriter Set AN/GRC-46

Starting Procedures

FSK Reception

Page Printer and Reperforator-Transmitter
Operation

Transmission on Teletypewriter Set AN/UGC-4

Page Printer and Reperforator-Transmitter Operation

Punching tape using Teletypewriter Set AN/UGC-4 (no
transmission).

Page Printer and Reperforator-Transmitter Operation (continued)

Punching Tape using reperforator-transmitter keyboard (no
transmission).

Page Printer and Reperforator-Transmitter Operation (continued)

Transmitting messages by tape

FSK Transmission

Radio Teletypewriter Set AN/GRC-46

Stopping Procedures

Section VII. Radio Set AN/FRC-93

Description

The AN/FRC-93 is an HF commercial single sideband radio set adapted for
military use. It is a continuous tuning radio with 200 kHz bands using the
Collins crystal packet. It can operate on either USB or LSB, and is designed to
be used in fixed or semifixed application. Current tactical speech security
equipment is not compatible with the AN/FRC-93; therefore, secure voice is not a
mode of operation. Major components of the AN/FRC-93 include the following:

a. Receiver/Transmitter RT-718 (Collins KWM-2/2A).

b. Power Supply PP-4151 (Collins 516F2).

c. Power Supply PP-3990 (Collins PM-2).

d. Control Group C-7515 (Collins 312B-5).

e. Amplifier AM-3979 (Collins 30L-1).

f. Crystal Unit Set CK-31 (Collins crystal packet CP-1).

Radio Set AN/FRC-93

Installation Procedures

a. Ensure power is turned off on all pieces of equipment prior to making
interconnections. Extreme high voltage exists within this equipment, and is
interlocked with the amplifier covers. Make no attempt to put the amplifier into
service until all compartment covers are in place.

b. Determine which configuration applies, and select applicable figure.

c. Wire and cable equipment to follow diagram.

d. Ground equipment.

e. Erect antenna.

Radio Set AN/FRC-93

Preliminary Checks

Radio Set AN/FRC-93

Receiver Tuning

Radio Set AN/FRC-93

Transmitter Tuning

Radio Set AN/FRC-93

VOX Adjustment

Radio Set AN/FRC-93

Amplifier Tuning

Check all antenna and coaxial connections to prevent damage to the set. Tune
and load transceiver as in section on receiver/transmitter tuning. Amplifier
ON-OFF switch is OFF.

*See Figure
1-12

Radio Set AN/FRC-93

Power Indications

*See Figure
1-13

CAUTION

Avoid transmitter operation between 5.0 and 6.5 MHz. In this range, the
second harmonic of the IF frequency is nearly the same as the desired frequency.
In transmit function, some of this energy will pass through the tuned circuits
and become false emission.

Section VIII. Radio Set AN/VRC-64

Operating Procedures

Section IX. Radio Set AN/VRC-12 Series

Installation Procedures

Radio Set AN/VRC-12 Series

Operating Procedures

Section X. NRI System AN/VRC-12

Installation Procedures

NRI System AN/VRC-12

Prestart Procedures

NRI System AN/VRC-12

Starting and Tuning Procedures

NRI System AN/VRC-12

Stopping Procedures

Section XI. Radio Set Control Group AN/GRA-6

Installation Procedures (with Radio Set
AN/GRC-106)

Radio Set Control Group AN/GRA-6

Operating Procedures

Section XII. Radio Set Control Group AN/GRA-39

Installation Procedures

Radio Set Control Group AN/GRA-39

Operating Procedures

NRI System AN/VRC-12

Installation Procedures (using the AN/GRA-39,
Receiver/Transmitter RT-524, and Switchboard SB-22/PT)

Presets and Adjustments

Section XIII. Radio Set AN/PRC-77/25

Operating Procedures

Section XIV. Radio Set AN/PRC-104A

Installation and Operating Procedures

a. Transportation and storage. The AN/PRC-104A is an ultra lightweight, HF,
manpack radio. The radio set and its components are contained, transported and
stored in Radio Set Case CY8291/PRC-104 (transit case). The transit case
normally should be kept closed. To unpack the equipment, unfasten the four
latches and remove the transit case cover. Each of the pieces of equipment fits
into a molded space. Upon receiving this radio set, ensure the equipment is
complete. Inspect the equipment for any shipping damage.

b. The components must be assembled (installed) for operation. Figure
1-16 shows how the components of the AN/PRC-104A are assembled to make the
set operational.

Press the pressure release valve button to equalize pressure before
unlatching the transit cover. Then unfasten the four latches securing the
cover to the transit case and remove the cover.

Remove the receiver/transmitter and amplifier/coupler from the transit
case. Ensure the connectors on the two pieces are completely engaged by
pressing the two together from the ends. Secure the two by using the
quick-connect/disconnect latches on the front and rear of the
amplifier/coupler. Tighten the latches until snug.

Attach the battery pack to the bottom of the receiver/exciter and the
amplifier/coupler. It is critical to ensure the connectors on the battery pack
and the amplifier/coupler are lined up. This is where the electrical
connections are made by the battery. Secure the assembly by using the two
quick-disconnect latches on the battery pack.

c. The Whip Antenna AT-271A/PRC has seven sections (Figure
1-17). Each section fits into the end of a wider section. A stainless steel,
plastic covered cable (or braided plastic cord), under spring tension, is
threaded through the sections to keep them together in the operating condition.
When the sections are folded, the cable keeps them together as a group and
prevents the loss of individual sections. Spring tension is provided by a spiral
spring in the base section. Spring section, Antenna Base AT-129/PR (Figure
1-17) is used to keep the antenna stable.

Remove antenna shock mount from the transit case.

Screw Antenna Spring Section AB-129/PR into the bottom section of the whip
antenna.

Pull on section 2, 3, 4, 5, 6, and 7. Insert section 2 into section 1.
Continue to assemble all sections in this manner.

CAUTION

Do not try to assemble this antenna from the smallest section (7) to the
largest (1). Doing so will put too much strain on the nylon cord inside the
antenna and cause it to break. Start assembly from the largest end(1).

Screw the entire assembly into the antenna socket on the radio (Figure
1-16).

Connect a handset to the radio set upper AUDIO connector.

The set is now ready to operate.

Radio Set AN/PRC-104A

Preoperational Checks

Radio Set AN/PRC-104A

Presets

Radio Set AN/PRC-104A

Energizing Procedures

Radio Set AN/PRC-104A

Tuning Procedures

Radio Set AN/PRC-104A

Test Procedures

When the radio has concluded its tuning procedure, perform an operational
test on the radio. The test procedures are as follows:

Change frequency by at least 1 kHz; then momentarily
press the handset PTT switch.

Listen for a 1-kHz tune tone. (Tuning is brief. It maybe 3 to 12 seconds.)

NOTE: Tune tone should terminate within 12 seconds. This indicates the
automatic antenna tuner is operating normally. A continuous, rapid beeping sound
in the handset indicates the radio has failed to tune properly (a tuning fault
exists).

Transmit using the handset. Press the PTT switch, and communicate with
another radio set on the test frequency. A sidetone in the handset earpiece
indicates transmission is satisfactory. (For fault tone, refer to the radio
troubleshooting procedure.)

Repeat the above procedures for test
frequencies spaced through the 2 to 30 MHz part of the radio spectrum to
test the auto tune feature. Your frequency manager has these frequencies.

Select a frequency for the time standard broadcast (multiples of 5 MHz;
for example, 5, 10, 15, 20 MHz). For this test, one frequency may be better
than another, depending on the time of day and station. You may not hear these
stations outside the United States.

Monitor the time standard broadcast and switch sidebands. Verify no change
in the pitch of the audible signals. This indicates the frequency accuracy of
the radio set is within specifications.

Turn the radio off. The test is complete. The radio set is good.

Radio Set AN/PRC-104A

Operating Procedures

Turn MODE switch to V-TR.

Turn SIDEBAND switch to USB or LSB (see SOI).

Set frequency to your net operating frequency (see SOI).

Turn ANT SEL switch to WHIP ANTENNA.

Turn VOLUME control to desired listening level. Power is applied at this
time through the VOLUME control.

NOTE: If a clicking sound is heard, the battery is a weak (20 volts or less)
and needs to be replaced.

Momentarily press and release the handset PTT switch.

Listen for l-kHz tune tone. Tuning is brief (3 to 12 seconds).

NOTE: Tune tone should terminate within 12 seconds. This indicates the radio
is tuned and ready for operation. A continuous, rapid beeping in the handset
indicates the radio has failed to tune properly (a tune fault exists). Refer to
the troubleshooting procedures or to organization maintenance.

To communicate with the AN/PRC-104A, use the handset as follows:

Press the PTT switch, transmit to another station, and release the PTT
switch to hear (receive) the other station.

Press to transmit, and release to listen.

Listen for sidetone in the handset earpiece. Sidetone indicates you are
transmitting.

Radio Set AN/PRC-104A

Modes of Operation

a. Voice.

Turn MODE SELECTOR switch to V-TR.

Adjust OFF/MAX/VOLUME switch to comfortable listening level.

Press handset PTT switch and talk, release it to receive.

b. CW.

Turn MODE SELECTOR switch to V-TR.

Adjust OFF/MAX/VOLUME switch to comfortable listening level.

Connect Leg Key KY-872 to upper AUDIO connector.

Press leg key to send and release it to receive.

c. Radio silence (voice or CW).

Turn MODE SELECTOR switch to V-RCV.

d. Remote operation (Figure
1-18).

e. The Radio Set Control Group AN/GRA-39 controls the remote operation of the
tactical radio set. It includes the Remote Control Unit C-2328/GRA-39, the Local
Control Unit C-2329/GRA-39, Handset H-189/GR, and carrying Bag CW-598/GRA39 (a
bag and a carrying sling).

NOTE: The AN/GRA-39 is not issued with the AN/PRC-104A.

Disconnect the H-250/U handset control cable from the upper AUDIO
connector on the receiver/transmitter.

Connect the control cable of the local unit, the C-2329/GRA-39, to the
upper AUDIO connector of the receiver/transmitter.

Connect the H-250/U control cable to the AUDIO connector on Local Control
Unit C-2329/GRA-39.

The remote unit C-2328/GRA-39 may be up to two miles from the radio set.
It is connected to the line terminals of the local unit by 600 ohm wire that
is connected to the line terminals of the remote unit.

NOTE: Any wire may be connected to any line terminal on the local and remote
control units.

Connect the control cable of the Handset H-189/GR, supplied with the
AN/GRA-39, to the audio jack of the Remote Control Unit C-2328/GRA-39.

f. Voice communications can be received and transmitted through the radio set
and can be controlled either locally or at the option of the operators.

g. The remote unit has a loudspeaker to monitor all received radio signals.
The volume is controlled by the VOLUME control knob on the receiver/transmitter.

Radio Set AN/PRC-104A

Stopping Procedures

Turn the OFF/MAX/VOLUME switch to OFF.

Radio Set AN/PRC-104A

Disassemble and Transport Procedures

To disassemble and transport the radio set--

Turn power off.

Remove the antenna and antenna shock mount (base) from the radio set.

Remove the antenna shock mount (base) from the antenna and place the base
in the space provided in the transit case.

Start at the tip (top end), fold the seven-section antenna, and place it
in the transit case.

Remove the handset and place it in the transit case. Remove the battery
pack from the receiver/transmitter-amplifier/coupler. Put the battery pack in
the transit case. Remove batteries from the battery case and transport them
separately.

WARNING

Only battery packs that are not activated may be placed in the transit case.
An activated battery pack must be transported and stored separately.

Place the receiver/transmitter-amplifier/coupler combination into the
transit case.

Replace the transit case cover, and fasten the four latches.

NOTE: The radio set is now ready for transport or storage.

Radio Set AN/PRC-104A

Operator Daily and Weekly PMCS

a. The operator must perform daily and weekly PMCS. Although it is not
specifically a part of daily or weekly PMCS, the radio set must be cleaned. PMCS
keeps the radio set operational; keeping the radio set clean is just as
important.

b. Clean the radio set when needed by--

Removing dirt, dust, grease, or other debris from external surfaces using
a cloth or brush moistened in clear water. Dry the equipment with a soft,
lint-free cloth.

Cleaning any dust or dirt from the connectors and pins with a
soft-bristled brush.

c. Check for corrosion or fungus on the radio set when preparing it for
operation or when you are operating it. During PMCS, separate the three units if
they are installed. Also, check the exterior surface controls and connectors for
signs of corrosion or fungus. Remove corrosion or fungus with a cloth and/or
brush moistened in cleaning solvent. Repaint any surfaces that need painting.

d. The following pages discuss the daily and weekly PMCS. The operator
performs daily PMCS when the equipment is operated. The operator performs weekly
PMCS when the equipment is not operated daily. However, daily PMCS also is
performed whenever weekly PMCS is performed. When performing PMCS, report items
that are broken or damaged beyond repair to the next higher maintenance level.
Any deficiencies you cannot correct must be reported on DA Form
2404.

Section XV. Radio Set AN/GRC-213

Description

a. The AN/GRC-213 is a lightweight (50 pounds), low power (20-watt) output,
HF radio set capable of short-to long-range communications. It uses the same
receiver-transmitter (RT1209/URC) as the AN/PRC-104A, but has no battery pack.
It operates from the vehicle power supply using amplifier/power supply
AM-7152/GRC-213 to filter and condition the vehicle power for the radio set. The
amplifier/power supply also amplifies and squelches (cut out the rushing noise)
the audio output to drive an external speaker and provides connection for an
AIN/VIC-l.

b. The radio set can be mounted in a wheeled or tracked vehicle, or installed
in a fixed location, such as a building or tent. When installed in a fixed
location, a power supply capable of providing 24 to 32 volts DC (26.5 VDC
nominal) must be used (for example, Generator Set 3 kW, 29 VDC, or Battery
Charger PP-1451/G or similar power supply). In vehicles equipped with the
Intercommunications Set (Intercom) AN/VIC-1, automatic retransmission is
possible from any single sideband radio, such as the AN/GRC-213, to any FM
radio, such as the AN/VRC-12 series (Figure
1-20).

Radio Set AN/GRC-213

Installation Procedures

a. Before operating Radio Set AN/GRC-213, check to make sure it is properly
installed in the mount. Ensure it is grounded and has an antenna connected to
it.

b. Connections for grounding the radio set to the mount are at the rear of
the radio set. Quick connect ground straps connect the components together and
ground the radio set to the mount. Make sure the ground straps are connected
properly to provide a proper ground. Do not depend on the metal to metal contact
between the components to ground the radio set. When operating from a stationary
position, connect a ground strap between the vehicle and a ground rod that has
been driven into the ground. This will prevent electrical shock when touching
the vehicle. (Refer to TC 11-6
for proper grounding techniques.)

c. The AN/GRC-213 uses any antenna designed for HF communications. The most
common are the 15-foot whip antenna, the half-wave (doublet) antenna, the
quarter-wave antenna and the NVIS antenna. Refer to Chapter 3 for
a list of the characteristics of these antennas.

d. Before operating your radio, ensure an antenna is installed and connected
to the radio set. Operating a radio with no antenna may cause serious damage to
the equipment. When using the whip antenna, be sure the correct number of
sections are installed (normally five each, three-foot sections).

Radio Set AN/GRC-213

Operating Procedures

Turn MODE switch to V-TR.

Turn SIDEBAND switch to USB or LSB (see SOI).

Set FREQUENCY to your net operating frequency (see SOI).

Turn ANT SEL switch to MIDDLE (BNC connector) position.

Turn VOLUME control to desired listening level. Power is applied at this
time through the VOLUME control.

NOTE: A clicking sound indicates low vehicle battery voltage (20 volts or
less). The vehicle should be running during operation of the AN/GRC-213 to
prevent draining the vehicle's battery. Before starting the vehicle, be sure the
radio is off to prevent damage to the radio.

Momentarily press and release the handset PTT switch.

Listen for a 1-kHz tune tone. Tuning is brief. It may be 3 to 12 seconds.

NOTE: Tune tone should terminate within 12 seconds. This indicates the radio
is tuned and ready for operation. A continuous, rapid beeping in the handset
indicates the radio has failed to tune properly (a tune fault exists). Refer to
the troubleshooting procedures or to organization maintenance.

To communicate with the AN/GRC-213--

Press the handset PTT switch, and speak into the mouthpiece of the
handset. Release the PTT switch to listen (receive) to the other station.

Press to transmit, and release to listen.

Listen for sidetone in the handset earpiece. Sidetone indicates you are
transmitting.

Adjust the SQUELCH control on the amplifier/power supply to allow the
distant stations to be heard when they transmit and to eliminate the
background noise.

CAUTION

Always listen before pressing the PTT switch to prevent interfering with
another station that may be transmitting.

Radio Set AN/GRC-213

Preoperational Checks

Radio Set AN/GRC-213

Presets

Radio Set AN/GRC-213

Energizing Procedures

Radio Set AN/GRC-213

Tuning Procedures

Radio Set AN/GRC-213

Stopping Procedures

Radio Set AN/GRC-213

Modes of Operation

Radio Set AN/GRC-213

Operator Daily and Weekly PMCS

a. The operator must perform daily and weekly PMCS. Although it is not
specifically a part of daily or weekly PMCS, the radio set must be cleaned. PMCS
keeps the radio set operational; keeping the radio set clean is just as
important.

b. Clean the radio set when needed by--

Removing dirt, dust, grease, or other debris from external surfaces using
a cloth or brush moistened in clear water. Dry the equipment with a soft,
lint-free cloth.

Cleaning any dust or dirt from the connectors and pins with a
soft-bristled brush.

c. Check for corrosion or fungus on the radio set when preparing it for
operation or when you are operating it. During PMCS, separate the three units if
they are installed. Also, check the exterior surface controls and connectors for
signs of corrosion or fungus. Remove corrosion or fungus with a cloth and/or
brush moistened in cleaning solvent. Repaint any surfaces that need painting.

d. The following pages discuss the daily and weekly PMCS. The operator
performs daily PMCS when the equipment is operated. The operator performs weekly
PMCS when the equipment is not operated daily. However, daily PMCS also is
performed whenever weekly PMCS is performed. When performing PMCS, report items
that are broken or damaged beyond repair to the next higher maintenance level.
Any deficiencies you cannot correct must be reported on DA Form
2404.

Radio Set AN/GRC-213

Operator Troubleshooting

Operator troubleshooting of the radio set is limited to fault isolation to a
replaceable unit or accessory. Use the operational indicators and audible tones
in the handset to isolate faults. The following table is an equipment
performance check (EPC). If a component is not performing as indicated in
the performance test, a higher level of maintenance is required. Use this
performance test as a troubleshooting guide.

Radio Set AN/GRC-213

Equipment Performance Check (EPC)

Presets

Section XVI. Radio Set AN/GRC-193A

Description

a. The AN/GRC-193A is a rugged, tactical, vehicular/base station, HF radio
set. The set's high power (100 to 400 watts) makes it capable of long-range
communications. It uses the same Receiver/Transmitter RT-1209/URC as the
AN/PRC-104A and the AN/GRC-213. It operates from the vehicle power supply. The
Amplifier/Converter AM-6879 squelches the audio output to drive an external
speaker. The radio set can be mounted in a wheeled or tracked vehicle; it can
also be installed in a fixed location, such as a building or tent. When
installed in a fixed location, a power supply capable of providing 24 to 32
volts DC (26.5 VDC nominal) must be used (for example, generator set 3 kW, 28
VDC, or battery charger PP-1451/G or similar power supply).

b. For the most part, the technical characteristics of the radio set are the
same as the AN/PRC-104A and the AN/GRC-213. However, the AN/GRC-193A has an
additional component, Amplifier/Converter AM-6879/GRC-193A. This component makes
it capable of radio teletypewriter operations. Additional equipment not issued
with the AN/GRC-193A (for example, AN/UGC-74(*) and TSEC/KG-84A) is needed for
radio teletypewriter operations. A tactical antenna remoting kit enhances the
operational flexibility of the AN/GRC-193A. The kit allows remoting of the
Antenna Coupler CU-2064/193A and the antenna 200 feet from the radio set. For
more information, see TM
11-5820-924-13.

Radio Set AN/GRC-193A

Installation Procedures

a. Before operating Radio Set AN/GRC-193A, ensure it is properly installed in
the mount. Make sure it is grounded and has an antenna connected to the radio.

b. Attach the ground strap to one of the ground terminals on front of the
antenna coupler. The other end is connected to the mount. Install a ground rod
and attach one end of a ground strap to the remaining terminal on the antenna
coupler and the other end to the ground rod. This will prevent electrical shock
when touching the vehicle. (See TC 11-6 for proper grounding techniques.)

c. Before operating the AN/GRC-193A, be sure an antenna has been connected to
the radio set. The AN/GRC-193Ais issued with a 15-foot whip antenna and two 50
ohm antenna kits (Doublet Antenna AN/GRA-50 and NVIS AS-2259/GR Antenna).

DANGER

There are 10,000 volts at the antenna terminal J4 when using the whip antenna
or J3 terminal when using the 50 ohm antenna. Do not remove during operation.
Extreme caution must be taken to ensure these terminals are at least 6 inches
from nearby objects such as cables, guy wires, brackets or ground leads.

Radio Set AN/GRC-193A

Operating Procedures

Make preoperational checks.

Make control presets.

Turn VOLUME control to desired listening level. Power is applied at this
time through the VOLUME control.

NOTE: A clicking sound indicates low vehicle battery voltage (20 volts or
less). Start the vehicle before powering up the radio set. Leave it running
while operating the AN/GRC-193A to prevent draining the vehicle's battery power.

Connect a handset to the UPPER audio receptacle of the RT1209/URC or the
AM-6545/GRC-193A.

Momentarily press and release the handset PTT switch.

Listen for a 1-kHz tune tone. Tuning is brief. It may be 3 to 12 seconds.

NOTE: Tune tone should terminate within 12 seconds. This indicates the radio
is tuned and ready for operation. A continuous, rapid beeping in the handset
indicates failure of the radio to properly tune (a tune fault exists). Refer to
the troubleshooting procedures or to organization maintenance.

To communicate with the AN/GRC-193A--

Press the handset PTT switch, and speak into the mouthpiece of the
handset. Release the PTT switch to listen (receive) the other station.

Press to transmit, and release to listen.

Listen for sidetone in the handset earpiece. Sidetone indicates you are
transmitting.

Adjust the SQUELCH control on the amplifier/converter to allow the distant
stations to be heard when they transmit and to eliminate the background noise.

CAUTION

Always listen before pressing the PTT switch to prevent interfering with
another station that may be transmitting.

Radio Set AN/GRC-193A

Preoperational Checks

Radio Set AN/GRC-193A

Presets

Radio Set AN/GRC-193A

Energizing Procedures

Radio Set AN/GRC-193A

Tuning Procedures

Radio Set AN/GRC-193A

Stopping Procedures

Radio Set AN/GRC-193A

Modes of Operation

Radio Set AN/GRC-193A

Preventive Maintenance Checks and Services
(PMCS)

a. PMCS of the AN/GRC-193A are required to keep the equipment in good
operating condition. They include before operation, during operation and after
operation checks. If the equipment is operated daily, perform maintenance each
day. If the equipment is maintained in a STANDBY condition (not used), perform
PMCS weekly.

DANGER

Before you operate, always keep in mind the cautions and warnings. This
equipment can seriously injure or kill if it is not operated safely and
properly.

b. The PMCS charts do not list routine checks, such as equipment inventory,
cleaning components, checking for frayed and damaged cables, replacing items not
in use, checking for loose hardware and safety wires, and corrosion or
receptacles and connectors. Do these things any time they need to be done. This
is a matter of good preventive maintenance.

Cleaning

Inspect the exterior of the radio set components. The exterior surfaces
should be free of dust, dirt, grease, moisture, fungus, rust, and corrosion.
Remove dust, moisture, and loose dirt with a clean soft cloth.

DANGER

Trichloroethane fumes are toxic. Provide thorough ventilation when it is
used. Avoid prolonged or repeated breathing of vapor. Do not use near an open
flame or hot surface. Trichloroethane is nonflammable, but heat converts the
fumes to a highly toxic phoagene gas. Inhaling the gas could result in serious
injury or death. Prolonged or repeated akin contact with trichloroethane can
cause skin inflammation. When necessary, use gloves, sleeves, and aprons the
solvent cannot penetrate.

Remove grease, fungus, and ground-in dirt from the equipment covers. Use a
dampened cloth (but not wet) with trichloroethane.

Remove dust or dirt from plugs and jacks with a brush.

CAUTION

Do not press the glass of the meter on the AM-6545 or the RT-1209 when
cleaning.

Clean the meter, front panels, and control knobs. Use a soft clean cloth. If
dirt is difficult to remove, dampen the cloth with water. Mild soap may be used
for more effective cleaning.

Radio Set AN/GRC-193A

Operator Troubleshooting

Troubleshooting of this equipment is based upon the operational check in the
daily operator PMCS. To troubleshoot the equipment, perform an operational
check. Proceed through this check until an abnormal condition or result is
observed. When an abnormal condition or result is observed, turn to the
troubleshooting procedure on the following pages and determine if there is a
similar condition in the symptom column. If the corrective measures indicated do
not correct the trouble, a higher category of maintenance is required. It is
assumed the Amplifier/Converter AM-6879 front panel fuse has been checked by the
operator, and the vehicular generating system or external power source is in
working order. These items are not listed in the check and corrective measure
column of the troubleshooting chart.

Radio Set AN/GRC-193A

Operator Troubleshooting

NOTE: Refer to troubleshooting flowchart in Figure
1-21. HCM means higher category of maintenance.

Section XVII. Single-Channel Ground and
Airborne Radio System (SINCGARS) and AN/TSC-124 (SCOTT)

SINCGARS

SINCGARS is a new family of VHF-FM combat net radios. SINCGARS is designed to
provide the primary means of command and control (voice and digital data up to
16 kb/s) for combat, combat support, and combat service support units. To help
the communications system survive, SINCGARS provides a resistance to jam (ECCM)
capability using single-channel offset or frequency hopping. SINCGARS also has a
built in data adapter to allow transmission of a wide range of analog and
digital data signals. Figure
1-22 shows a SINCGARS.

AN/TSC-124 (SCOTT)

a. The AN/TSC-124 is a single-channel, tactical satellite communications
terminal. It provides highly survivable, antijam and high altitude
electromagnetic pulse-protected (HAEMP) satellite communications for
nonstrategic forces, contingency units, special operations units, and theater
forces. It will provide critical command and control communications and replace
existing terrestrial communications nets. The AN/TSC-124 will survive when the
enemy has degraded or destroyed other communications, although voice
communications will be possible. (See Figure
1-23.)

b. The AN/TSC-124--

Consists of the terminal mounted in S-250 shelter, prime mover, and
trailer-mounted power generator. Backup power is provided by the prime mover.

Accepts up to four data/voice inputs from UCID 2500 feet away from the
terminal.

Operates in both DAMA and TMDA modes.

Provides electronic ECCM capability.

Can accept over-the-air rekeying of TRANSEC devices.

Regency Net System

a. The Regency Net System provides survivable HF radio command, control, and
communications which pass messages accurately and rapidly for US
Commander-in-Chief, Europe and Pacific and internal unit communications within
their major subordinate commands. The Regency Net System includes the force
terminal which is a multichannel terminal housed in a S-280 shelter and a team
terminal which is a single-channel terminal mounted in a 1/4-ton vehicle. For
the purpose of this manual, only team terminal (Figures 1-24
through 1-26) will be discussed.

b. The AN/GRC-215 team terminal--

Consists of a single channel 100-watt HF transceiver which is vehicular
mountable or manportable.

Provides secure data and voice communications to assigned force terminals.

Is compatible with force terminals in all modes except radioteletype.

Utilizes three microprocessors at data receipt ports to control regency
net connectivity, provides radio control, processes messages, and isolates
faults.

Has printer port for interface with either a force terminal thermal
printer or the AN/UGC-144 control terminal.

Operates on the move or at halt utilizing 12/24 V DC vehicle power.

Possesses active ECCM.

Is interoperable with currently fielded single-channel HF radios.