737 MAX Flight Crew Operations Manual
Communications -
Controls and Indicators
5.10.2
MN-FLT-OH-201
4
Radio Tuning Panel OFF Switch
Push –
• disconnects the panel from the communication radios
• switch illuminates (white).
5
HF Sensitivity Control
Rotate – adjusts the sensitivity of the on–side HF receiver.
6
Radio Tuning Light
Illuminated (white) - indicates the selected radio.
7
Offside Tuning Light
Illuminated (white) –
• the radio normally associated with this panel is being tuned by another
radio tuning panel, or
• the radio tuning panel is being used to tune a radio not normally
associated with this radio tuning panel.
8
Frequency Selector
Rotate - selects frequency in the STANDBY frequency indicator:
• first digit is always 1
• outer selector changes second and third digits in 1 MHz increments
• inner selector changes fourth, fifth, and sixth digits in 8.33 KHz
increments.
• For airplanes with ACARS, tuning above maximum or below minimum
frequency displays DATA in Frequency Indicator.
9
VHF TEST Switch
Push –
• removes automatic squelch feature, permitting reception of background
noise and thereby testing receiver operation
• improves reception of weak signals.
10
AM Light
Illuminated (white) – HF AM is selected.
Extinguished – HF USB is selected.
11
AM Switch
Push – sets the AM (amplitude modulation) or USB (upper side band) mode for
the selected HF.
October 26, 2021
