User's Manual

A-2
RESULTS
If the installed system passes all of the applicable EMI tests, then no further action is required. If
interference is observed then the interference must be assessed against the appropriate standards
of airworthiness for the system in question. For example it is permissible for a VFR certified GPS
to lose navigation capability while the TFM-500 unit is transmitting, providing that it recovers
properly and promptly, but it is not permissible for an IFR Approach certified GPS to affected in the
same way. A complete discussion of all the standards of airworthiness to be applied in assessing
EMI effects is beyond the scope of this document.
PROCEDURE
A. Operate the TFM-500 transmitter on the following frequency for at least 20 seconds.
Observe the GPS for any degradation in satellite status or availability or flags.
FREQUENCIES GPS #1 GPS #2
TFM-500 PASS FAIL PASS FAIL
143.180 MHZ
143.1825 MHZ
157.5000 MHZ
157.5425 MHZ
512 MHZ
NOTES:
B. Determine if the image frequency for the VHF Comm falls within the range of the TFM-500.
If so, select a set of frequencies that will cause the TFM-500 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-500 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-500 to 142.8000 MHZ.