User's Manual

3-7
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 TDFM-600/6000 unit is transmitting,
providing that it recovers properly and promptly, but it is not permissible for an IFR Approach
certified GPS to be 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 TDFM-600/6000 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
TDFM-600/6000
PASS FAIL PASS FAIL
143.2125 MHz
143.2250 MHz
157.5375 MHz
157.5500 MHz
512 MHz
NOTES:
B. Determine if the image frequency for the VHF Comm falls within the range of the TDFM-
600/6000. If so, select a set of frequencies that will cause the TDFM-600/6000 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 TDFM-
600/6000 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 TDFM-600/6000 to 142.8000 MHz.