User's Manual

TECHNISONIC INDUSTRIES LIMITED
www.til.ca
TFM-550 Installation & Operating Instructions TiL 99RE262 Rev A Issue 8
A-3
B. Determine if the image frequency for the VHF Comm falls within the range of the TFM-550. If so,
select a set of frequencies that will cause the TFM-550 to be set as close as possible to the
image frequency. Any one of the many possible sets will suffice. Record those values in the
spaces provided in the following chart. Modulate the TFM-550 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 TFM-550 to 142.8000 MHz.
(Note: Where indicated by an asterisk (*), required action is to switch ATC-550 on and off as often
as necessary.)
FREQUENCIES RESULTS
VHF #1 TFM-550 PASS FAIL
118 34
118 45
135.975 138
121.15 157.5
131.25 157.5
128 *
Image: