General

You use these components to operate the VHF radio:

• Microphone or headset

• Control wheel mic switch

• Radio communication panel (RCP)

• Remote mic switch

• Audio control panel.

Receive Operation

You use the radio communication panel and the audio control panel to receive transmissions on the VHF radio.

On the audio control panel, push the receiver volume control for the VHF radio. Turn the control to adjust the volume from the VHF radio.

You hear audio on the headset and the flight interphone speakers. To hear sound from the flight interphone speakers, push the speaker (SPKR) volume control to turn on the speaker. Turn the control to adjust the volume of sound from the speaker. В начале

When you apply power to the airplane, the radio communication panels (RCPs) are on. Initially, RCP 1 tunes VHF 1 and RCP 2 tunes VHF 2. Push the VHF microphone selector switch for the VHF radio you want to use. A light above the switch comes on to show which radio the panel controls. When you push the audio control panel microphone selector switch, the VHF receiver volume control is automatically selected. The frequency indicators show VHF radio frequencies. The VHF transceiver tunes to the frequency in the active frequency indicator.

Use the frequency selectors to tune the radio to a new

frequency. The standby frequency display shows the new

frequency.

When you are sure the frequency is correct, push the frequency transfer switch. The active frequency indicator shows the new frequency. The VHF radio uses the new frequency.

Listen to the audio from the VHF radio on the speaker or

headset. Adjust the volume control switches on the audio

control panel for a comfortable sound level.

Transmit Operation

Make sure the active frequency indicator shows the frequency you want to transmit. Make sure the frequency you select is a valid transmit frequency.

Push the microphone selector switch on the audio control panel for the VHF radio.

Listen for transmissions on the frequency you selected. When the frequency is clear and you want to transmit a message, key the mic and speak into it. You hear sidetone in the headphone and muted sidetone from the speaker. The flight interphone system mutes the sidetone to the speaker when you use the boom mic or the hand mic. Приглушать звук

You can continue to transmit and receive on the frequency you

selected.

General

The VHF transceiver has built-in test equipment (BITE). You start the test on the front of the VHF transceiver.

When you start the test, the built-in test equipment examines the input from the control panel or ACARS management unit, the internal circuits and processors of the transceiver, and the output to the antenna.

Test Operation

When you push the TEST switch, the transceiver does these checks:

• Monitors the power supply

• Does a test of the memory devices устройство памяти

• Does a test of the input from the control panel or the ACARS management unit

• Does a test of the frequency synthesizer

• Keys the transmitter for 100 ms at 128.475 MHz and does a test of the modulation, power and VSWR (voltage standing wave ratio)

• Does a test of the receiver automatic-gain-control and

squelch operation.