190-01007-C1
GTN Xi Part 23 AML STC Maintenance Manual
Rev. 1
Page 7-6
COM Carrier Squelch Check (COM Software v2.30 or Later)
COM carrier squelch settings allow adjustment of the carrier signal strength required to break squelch for
the COM receiver.
The COM carrier squelch level adjustment reduces the sensitivity of the COM receiver. Elevated, ambient
RF interference levels in certain flight environments, such as aircraft operating busy airport environments
or aircraft with equipment installed that interferes with the COM radio, may require adjustment of the
COM carrier squelch to reduce undesired squelch breaks.
Table 7-3 COM Carrier Squelch Selections
Table 7-4 lists approximate levels when the carrier squelch opens for various COM Carrier Squelch
settings. Installations requiring adjustment generally use a COM carrier squelch setting of 33 or higher for
25 kHz spacing and 0 for 8.33 kHz spacing.
Table 7-4 COM Carrier Squelch Selections
Notes:
[1] The COM carrier squelch range (0-100) is a linear response.
Selection
Description
Basic
Applies a COM carrier squelch value of 0 to 25 kHz and 8.33 kHz spacing.
Advanced
Allows the adjustment of COM carrier squelch values.
Spacing
Allows the adjustment of COM carrier squelch values for 25 kHz and 8.33 kHz
spacing separately.
Squelch
The COM carrier squelch is adjustable in the range of 0 to 100. The default value is
0. Decreasing the value allows the carrier squelch to be broken with low signal
levels. Increasing the value requires higher signal levels to break carrier squelch.
COM RF Squelch
Setting
[1]
Carrier Squelch Open
Approximation
0
-87.0 dBm
25
-84.5 dBm
50
-82.0 dBm
75
-79.5 dBm
100
-77.0 dBm
