Radios

Overview

UHF-AM Radio Set AN/ARC-164 (UHF)

Two-way voice communication in frequency range of 225.000 to 399.975MHz.

VHF-AM Radio Set – AN/ARC-186 (VHF)

Two-way voice communication in frequency range of 116.000 to 151.975MHz

VHF-FM Radio Set – SINCGARS (FM-1 or 2) AN/ARC-201D

Two-way voice communication and transmission in frequency range of 30.000 to 87.975 MHz with frequency hopping, scan, and secure capability (FM-1 and FM-2).

AN/ARC-231 SATCOM RADIO

Not Implemented in DCS

Control of the radios is via a combination of panels;

• The RFD displays the current frequencies of each radio,
• MFDs & MFK are used to change frequencies,
• communications system control panel provides volume controls to each pilot,
• combined with channel select & radio select switches.  

Communications System Control Panel

The communication system provides two way communications between the crewmembers and allows the crew to communicate outside the helicopter through four communication radios. Radio selection and audio volume are controlled through the communication system control (CSC) panel.

1. Volume Control Knob. Controls audio output level to the headset
2. Radio Monitor Switches. Controls audio output level for each radio. A pulled knob inhibits audio for the selected radio
3. NAV Switches. The NAV switches are not used in the OH-58D
4. ICS Rotary Switch. When operating in “NORM”, you must key the ICS
5. VOX Control. Causes the intercom system to be voice activated for crew communications
6. Transmit Selector Switch. Allows pilot to remotely select a radio if the CSC transmit select switch is in remote (RMT) position.
7. MIC Switch. Allows pilot to select between MIC1 & MIC2.

 

Radio Select Switch

A five-position switch that is used to select a radio for transmit. Radio selections are also made with the radio select switch located on the pilot collective control head. The channel and frequency to which each radio is tuned is displayed on the RFD Setting the desired frequencies and modes into the radios is accomplished using the MFK and MFD.

Pressing to the 1 (upper left) position selects FM-1

Pressing straight down on 5 (center position) selects FM-2 Pressing to the 2 (upper right) selects UHF Pressing to the 3 (lower right) selects VHF Pressing to the 4 (lower left) SATCOM, if installed (not implemented in DCS),

As a radio is selected, an arrow will appear beside the frequency of that radio on the MFD. This arrow will point to the right or left indicating that the pilot or CPO respectively is selected to transmit on that radio. (see Figure 133 - Remote Frequency Display) 

Channel Select Switch

CHAN select switch — Located on the Pilot collective head and CPO CSC panel

A four-position, center spring-loaded to neutral switch that works in conjunction with the MFD, MFK, and RFD.

Pressing the switch to the CHAN UP position changes the channel number and frequency of the radio currently selected for transmitting to the next higher channel and frequency stored on the frequency list.

Pressing the switch to the left, or KYBD (keyboard), position activates the keyboard if a manual frequency is currently selected on the RFD, to allow the entry of manual channels and frequencies for the radios selected for transmitting.

Pressing the switch to the DN (down) position changes it to the next lower channel and frequency stored.

Remote Frequency Display

The Remote Frequency Display (RFD) acts as the primary display for the radios. The RFD displays the Pilot and Copilot (see Left & Right arrows indicated #4 & #5 below) selected radios, channels and modes.

The RFD is primarily a display and cannot make inputs to change channels, frequencies or radio selection. These inputs are made through the MFD COMM pages or via the Pilot and Copilot Channel Select controls or Communication System Control panels.

1. List of available radios:
   1. FM1
   2. UHF
   3. VHF
   4. Not Used
   5. FM2
2. Channel Indicator
   • M: Manual frequency
   • 01-19: Selected channel
3. Selected frequency
4. Copilot selected radio indicator
5. Pilot selected radio indicator
6. Brightness control rheostat
7. CIPH mode indicator
8. Copilot CIPH mode selector
9. Pilot CIPH mode selector
10. Test button. Holding test button will display test pattern