Garmin GNC 420 Maintenance Manual page 82

5.7.3.19 Spurious Response—VOR/LOC
1. Tune the VOR receiver to 117.95 MHz.
2. Verify the input signal level of an undesired image frequency of 77.15 MHz required to
produce a detector-carrier (AGC) level obtained at the VOR/LOC IF AGC J6-7 output with a
-93 dBm Standard VOR Audio Test Signal is not less than -13 dBm.
Input Signal Level______NLT -13 dBm
3. Repeat the test at a LOC frequency of 111.95 MHz and an undesired image frequency of
71.15 MHz.
_____OK
400 SERIES MAINTENANCE MANUAL
P/N 190-00140-05
Page 5-31
Rev. C