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GNS 400W Series Maintenance Manual
Page 4-51
190-00356-05
Rev. A
VOR OBS Bearing Accuracy
The bearing information when measured through the VLOC SERIAL OUT J10-10 must not have
an error in excess of 2 degrees using a Standard VOR Test Signal and a Precision Track Selector
or similar device at 60, 150, 240, and 330 degrees in course angle.
Selectivity (Bandwidth)
The frequency response must not vary more than 6 dB as measured by the NAV IF AGC J6-7
voltage over the frequency range fc + 16.5 kHz to fc - 16.5 kHz where fc is the assigned channel
frequency.
Localizer (Bandwidth)
The course deviation measured through VLOC SERIAL OUT J10-10 must be 0 ddm ± 0.0093
ddm when using the Standard Localizer Centering Test Signal as the RF frequency is varied from
fc + 9 kHz to fc - 9 kHz from the assigned channel.
Nose Bandwidth: The input signal level required to produce the reference NAV IF AGC J6-7
voltage must not vary more than 6 dB over the input signal frequency range of fc + 9 kHz to fc -
9 kHz from the assigned channel frequency. (Optional Test).
Skirt Bandwidth: At frequencies of fc + 36 kHz and fc - 36 kHz the input signal level required to
produce reference NAV IF AGC J6-7 voltage must be at least 69 dB greater than the level
required to produce reference AGC voltage at the assigned channel frequency.
Spurious Response
VOR
With the VOR receiver tuned to 117.95 mHz, the input signal level of an undesired image
frequency of 77.15 mHz required to produce a detector-carrier (AGC) level obtained at the NAV
IF AGC J6-7 output with a -93 dBm Standard Localizer Audio Test Signal must not be less than -
13 dBm.
Localizer
With the Localizer receiver tuned to 111.95 mHz, the input signal level of an undesired image
frequency of 71.15 mHz required to produce a detector-carrier (AGC) level obtained at the NAV
IF AGC J6-7 output with a -93 dBm Standard Localizer Audio Test Signal must not be less than -
13 dBm.
Centering Accuracy
The centering error measured through VLOC SERIAL OUT J10-10 must be less than 0.00465
ddm (4.5 millivolts (5%)) using a Standard Localizer Centering Test Signal.
