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Page 4-48
GNS 400W Series Maintenance Manual
Rev. A
190-00356-05
Verify the following:
Between the limits of -99 dBm and -13 dBm input of a standard VOR audio test signal, the
difference between the maximum and the minimum VOICE/IDENT audio output levels must not
exceed 3 dB.
Localizer
Measure at NAV AUDIO HI J6-16 with respect to NAV AUDIO LO (GND) J6-17. Must be in
IDENT mode to pass 1000 Hz tone.
Verify that between the limits of -86 dBm and -33 dBm input of a standard localizer audio test
signal, the difference between the maximum and the minimum VOICE/IDENT audio output
levels is not greater than 3 dB.
VOR Audio Sensitivity
This test is measured at NAV AUDIO HI J6-16 and NAV AUDIO LO J6-17. Apply a
-103.5 dBm RF level to the RF input. Must be in IDENT mode to pass 1000 Hz tone.
Verify the audio SINAD is not be less than 6 dB with a standard VOR audio test signal at RF
frequencies of 108.00 mHz, 112.50 mHz, 112.55 mHz, and 117.95 mHz.
Localizer (Optional Test)
Measure at the NAV AUDIO HI J6-16 and NAV AUDIO LO J6-17 outputs with a standard
localizer audio test signal at RF frequencies of 108.10 mHz and 111.95 mHz. Must be in IDENT
mode to pass 1000 Hz tone.
Verify the audio SINAD is not be less than 6 dB.
Receiver Quieting
Apply a -86 dBm RF level to the RF input.
Verify the audio SINAD is not be less than 25 dB when measured at the NAV AUDIO HI J6-16
and NAV AUDIO LO J6-17 outputs with a Standard VOR Audio Test signal at 108.00 mHz.
Ident/Voice Tone Ratio
Apply a -67 dBm RF level applied to the RF input.
Verify the following: The ident/tone ratio must not be less than 20 dB when measured at the
NAV AUDIO HI J6-16 and NAV AUDIO LO J6-17 outputs with a Standard VOR Audio Test
signal with modulation frequency of 1020 Hz at 108.00 mHz or with a Standard Localizer Audio
Test signal with modulation frequency of 1020 Hz at 108.10 mHz.