Northern Airborne Technology NTX User Manual

Page 37

NTX138 Installation Approval Test Procedure

Rev. 1.00

Aug 31, 2001

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
NTX138 unit. If so, select a set of frequencies that will cause the NTX138 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 NTX138 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 NTX138 to
142.8000 MHz.

FREQUENCIES RESULTS

VHF #1

NTX138 PASS

FAIL

135.975 138.0000

121.150 157.5000

131.250 157.5000

Image: