Garmin GNC 420 Maintenance Manual page 80

5.7.3.12 VOR Course Deviation Sensitivity
1. Apply a standard VOR deviation signal at 108.00 MHz, –103.5 dBm RF level to the RF
input. at a radial of 160 degrees 'FROM'.
2. Apply a Precision Test Selector or similar device at 150 degrees in course angle.
3. Measure at the VOR/LOC +LEFT J6-5 and VOR/LOC +RIGHT (VOR/LOC COMMON) J6-
6 outputs.
Course Deviation Output______150 mV ±30mV
5.7.3.13 Localizer Course Deviation Sensitivity
1. Apply a standard localizer deviation signal of 108.10 MHz, at a –103.5 dBm RF signal to the
RF input.
2. Measure at the VOR/LOC +LEFT J6-5 and VOR/LOC +RIGHT (VOR/LOC COMMON) J6-
6 outputs.
3. Verify the magnitude of the course deviation output is greater than 50% (45 mV) of the
nominal output (90 mV).
Course Deviation Output ________ (>45 mV)
5.7.3.14 TO-FROM Indicator
1. Apply a VOR standard test signal @ -93dBm.
2. Select RF signal input bearings of -75 degrees, 0 degrees and +75 degrees from the selected
radial and verify that TO/FROM state does not change.
3. Measure at VOR/LOC +TO J6-1 with respect to VOR/LOC +FROM J6-2. When indicating
TO, 225 mV 75 mV should be present. When indicating FROM, -225 mV 75 mV should
be present.
_____OK
5.7.3.15 Centering Accuracy
Apply a standard localizer centering test signal. Verify the centering error measured at VOR/LOC
+LEFT with respect to VOR/LOC +RIGHT (VOR/LOC COMMON) is less than 4.5 mV (5%).
Centering Error______< 4.5 mV
400 SERIES MAINTENANCE MANUAL
P/N 190-00140-05
Page 5-29
Rev. C