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a
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The radio receivers and transmitter are located in the aft part of the fuselage and are accessible through the fuselage access door. (See figure 11.) All tuning dials, switches, and controls including the
radio filter and relay box, are grouped together on the right side
of the fuselage. (See figure 10.) The
radio contactor is located on the left side of the instrument
panel. (See figure 5.)
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b
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This radio installation incorporates a control box composed of individual controls for three separate receiver units of various range: from 3 to 6 mc, from 190 to 550 kc and from 6 to 9.1 mc. To operate these receivers, move the battery switch from "OFF" to the "CW" (continuous wave) or the "MCW" (modulated continuous wave)positions. Place the "TEL" switch to either "A" or "B" to correspond to the jack used for the headset plug. Set the filter switch box control to "RANGE," "VOICE," or "BOTH," as desired. (See figure 9.) Tuning is accomplished with the large "TUNING" knob while adjusting for suitable volume with the "INCREASE OUTPUT" control knob. The radio call letter plate is attached to the right longeron aft of the cabin control handle assembly. (See figure 10.) |
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c
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Two transmitters are installed, only one being used at a time, and are preset with the different frequencies recorded on the "WRITE IN" space on the transmitter control. When transmitting, move the "TRANSMITTER SELECTION" switch to the frequency desired. (See figure 9.) Set the "TRANSMITTER POWER" toggle switch to "ON." (See figure 9.)
It requires 15 seconds to warm up the transmitter tubes. Set the
emission switch to "TONE," "CW," or "VOICE," as required. (See
figure 9.) Be sure that the radio
contactor on the instrument panel (figure 5) is properly adjusted.
Set the clock switch (figure 5) to the "RUN" position and the contactor switch (figure 5) on the radio contactor to the "IN" position and leave these switches set in these positions throughout the entire flight. Tne purpose of this contactor is to automatically cut in the No. 1 transmitter for approximately 13 seconds at every revolution of the clock hand. While the clock hand is inside the angle marked on the clock face all sets are cut out except the No. 1 transmitter. If the pilot is transmitting a message he should observe the contactor clock hand at all times to determine when he is "ON" and "OFF" the air. If the emission switch is on "VOICE," press the "PRESS- TO- TALK" button on the throttle control (figure 8) and talk clearly and distinctly into the microphone. In the "VOICE" position the transmitter dynamotor will not start until the "PRESS- TO- TALK" button has been closed. Side tone should be heard distinctly whenever transmitting. With the emission switch on "TONE" or "CW" the dynamotor will be running continuously but the transmitter will not be "ON THE AIR" until the transmitter key is pressed.
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d
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The "TRANSMITTER POWER" toggle. switch should be left "ON" throughout the flight to avoid repetition of the 15second "WARM-UP" period. |
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e
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To reduce battery drain and increase dynamotor life, the emission selector switch should remain on "VOICE," unless continued use on "TONE" or "CW" is anticipated. (See figure 9.) |
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WARNING: The dynamotor generates 600 volts, dc. FEEL IT to determine that it is not running before attempting to connect or disconnect a transmitter or a power plug.
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f
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While tuning up the antenna circuit of the transmitters, do NOT touch the antenna when the power is "ON." |
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g
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The radio crash switches provided on the right side of the cockpit, outboard of the radiator shutter control handle, are employed by the pilot to destroy the identification radio when there is danger of this confidential radio falling into the hands of the enemy. The detonator installed in the radio destroys all wiring when set off by either, the automatic device or the switches in the cockpit. The automatic device is set off by acceleration during a crash landing. To destroy the radio during or after a regular landing the pilot must push both button switches simultaneously. Pressing one push button will not set off the detonator. The automatic unit is a separate device and is located adjacent to the radio it protects. |
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WARNING: Never actuate the two push buttons
unless it is desired to destroy the radio equipment. The push
button bracket is painted red with "DANGER" lettered on it for
quick identif ication.
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