HEADQUARTERS OH-58A, Technical Manual

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TM 55-1520-228-10
Change 11 3-5
SECTION I. COMMUNICATIONS
3-6. COMMUNICATIONS SYSTEM CON-
TROL, C-6533/ARC.
3-7. DESCRIPTION – COMMUNICATIONS
SYSTEM CONTROL.
The communications system control, C-6533/ARC (fig-
ure 3-2) provides an intercommunicates capability and
control of radio communications. Two of the control pan-
els are installed on the instrument panel, one each for
the pilot is installed on the right side overhead in the
passenger compartment. The control panels may be
used in any one of three different modes as determined
by the setting of switches and controls on the panel.
3-8. CONTROLS AND FUNCTIONS – COM-
MUNICATIONS SYSTEM CONTROL.
Refer to figure 3-2.
3-9. OPERATING PROCEDURES – COM-
MUNICATIONS SYSTEM CONTROL.
a. Modes of Operation. The three modes of op-
eration are two-way radio communication, radio receiv-
er monitoring, and intercommunications within the
helicopter.
b. Operation.
(1) Receiver switches - As desired.
(2) VOLume control - Adjust.
(3) HOT MIKE switch - As desired.
(4) Transmit-Interphone Selector - As required.
3-10. VHF/FM RADIO SET.
3-11. DESCRIPTION – VHF/FM RADIO
SET.
The AN/ARC-114 and AN/ARC-114A radio sets provide
two-way frequency modulated (FM) narrow band voice
communications and homing capability (Number one
unit only) within frequency range of 30.00 to 75.95 MHz
on 920 channels for a 50-mile distance as limited by line
of sight. A guard receiver incorporated in the set is fixed
tuned to 40.50 MHz. Retransmission of voice, CW or
X-mode communications is possible when a second set
is installed in the helicopter. The radio sets are marked
VHF/FM COMM and are installed in the center console.
Antenna location is located as shown in figure 3-1.
3-12. CONTROLS AND FUNCTIONS – VHF/
FM RADIO SET.
Refer to figure 3-3.
NOTE
When transmitting and/or receiving on
VHF (FM) in secure mode, do not key or
transmit simultaneously on any other
transmitter.
3-13. OPERATING PROCEDURES – VHF/
FM RADIO SET.
a. Transmit/Receive.
(1) Function selector - As desired.
(2) Frequency - Select.
(3) RCVR TEST - Press to test.
(4) AUDIO - Adjust.
(5) Transmit.
(a) Transmit-Interphone selector - Number
1 position (Number 5 position for second FM set).
(b) RADIO transmit switch - Press.
b. Homing.
NOTE
FM homing capability is not provided for
ATAS equipped helicopters.
(1) Function selector - HOMING.
(2) AUDIO - Adjust.
(3) Observe homing indications on the radio
bearing heading indicator.
c. Retransmission.
NOTE
Crew transmission may also be made
while in RETRAN mode.
(1) Frequencies - Select (Both FM sets).
NOTE
Frequencies must have a minimum of
five MHz difference, such as 30.00 MHz
and 35.00 MHz.
(2) Communications - Establish with each facili-
ty by selecting number 1 position and then number 5
position on the Transmit-Interphone selector.