Northern Airborne Technology NPX136D User Manual

Page 20

NPX136D Installation Approval Test Procedure

Rev. 1.00

Apr 22, 2004 Page 3 of 7

E NG-FORM: 634-0100.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

Determine if the image frequency for the VHF Comm falls within the range of the
NPX136D unit. If so, select a set of frequencies that will cause the NPX136D to
be set as close as possible to the image frequency. Any one of the many
possible sets will suffice. Record these values in the spaces provided in the
following chart. Modulate the NPX136D transmitter on the following frequencies
for at least 20 seconds. Listen for any noise or detected audio signals on the
VHF comm.

Example - Bendix/King KY 196A:
The first IF frequency is 11.4 MHz. The L.O. is above the received frequency
(high side injection), therefore the image frequency is 22.8 MHz above the
selected frequency. Set the KY 196A to 120.000 MHz and the NPX136D to
142.8000 MHz.

FREQUENCIES RESULTS

VHF #1

NPX136D PASS

FAIL

135.975 138.0000

121.150 157.5000

131.250 157.5000

Image: