(line of sight) between the search aircraft and the radio set. The AN/PRC-63 radio set can be worn as part of the aircrewman’s flight clothing or life jacket; it is secured to the garment by a strap attached to the slots in the battery housing. The automatic deployment device supplied with the radio set, when suitably connected to the parachute harness of the aircrewman by the user, will allow automatic transmission of the beacon tone upon parachute deployment. The radio can also be packed in a seat pack and, with the same deployment device suitably connected, can be automatically placed in beacon tone transmission mode upon ejection from the aircraft. The lanyard attached to the deployment device has been designed to withstand a pull force of 20 pounds without breaking. The downed aircrewman may remove the radio set from his flight clothing, life jacket, or survival kit and change its mode of operation to either voice transmit or voice receive by pressing the appropriate end of the rocking toggle actuator. In the event that he becomes injured, disabled, or otherwise incapable of selecting the desired mode of operation, the radio set will continue to transmit MCW beacon signals until the battery power is exhausted. Function and Use of Operating Controls The function and use of the operating controls are described in table 5-1. NOTE: When POWER ON/OFF actuator is in OFF position or in ON position with the deployment device installed, all other operating controls are disabled. The radio set can be held in either hand and operated by the thumb or fingers, respectively. In the normal operating position, the speaker/ mike faces the operator. NOTE: During operation, the radio set must be held in the upright position (antenna vertical), or loss of transmission or reception will result. For best results, hold the radio set approximately 1 to 2 inches from the mouth when speaking, or ear when listening. In the receive mode the sound is con- trolled by the volume control knob, which is located in the upper corner of the radio set (opposite the flexible whip antenna) and marked VOLUME MAX. Full clockwise rota- tion gives maximum volume; full counter- clockwise rotation gives minimum volume. The sound of the beacon monitoring tone is also controlled by this knob. NOTE: Neither the beacon nor voice- transmitter output is affected by the position of the volume control knob. Table 5-1.—Operating Controls and Functions Control Function POWER OFF Radio set is in storage condition. POWER ON Radio set is in beacon mode of operation. POWER ON Radio set is in standby condition ready for Deployment device installed automatic activation. POWER ON Radio set is in receive mode. RECEIVE VOICE PRESS AND HOLD POWER ON Radio set is in transmit mode. TRANSMIT VOICE PRESS AND HOLD A 5-6