Revision A
T-48 90 008 026
2-11
2.11.1 Mode 3A/C Automatic Sequence of Transponder Tests
Upon energizing the Transponder Under Test, the T-48 will recognize the transponder as having only Mode
3A and/or Mode C capabilities. The appropriate menu will be initiated and shown on the display.
The operator may now choose to select the Automatic sequence or the Manual sequence of tests. By
depressing the
INTERROGATE
switch (as indicated on the display), the automatic sequence will
commence.
The tests will proceed in order (Figure 2-6) and conclude at the POWER, RCVR & FREQ test page. The
automatic mode does not display results of an individual test as long as the tests performed “PASS”. Pulse
Width, Pulse Spacing and Data Pulse measurements are also performed during the Automatic sequence of
tests.
If a failure occurs in any one test, the Test Set will stop the automatic sequence and display the failure.
By stopping the test sequence, the operator is alerted to continued and potential failures if testing is
resumed. Once the sequence is stopped due to a failure, the operator may override and continue testing by
depressing the
INTERROGATE
button. The T-48 will then proceed to the next test in sequence. The
operator may also choose to repeat the test by toggling the
STORE/REPEAT
switch to initialize the failed
test a second time. By leaving the
STORE/REPEAT
switch in the
REPEAT
position, the T/S will
continuously cycle the selected test until the switch is returned back to the center position.
When all tests are complete, with no failures, the T-48 test sequence will end with an alternating display of
measured power, receiver sensitivity, and frequency. The second page displayed, shows power measured in
watts.
When utilizing the Omni Directional Antenna, power, frequency and sensitivity measurements will not be
displayed. The decoded aircraft 4096 code and altitude are shown.
[End of Page]
MODE 3A/C XPDR
INTERROGATE TO TEST
POWER, RCVR & FREQ
54dB–75dB 1090.0 MHz
FAIL 09% REPLY
CONTINUE: PRESS INT
1234 10,000’
NO MEASURED POWER
POWER, RCVR & FREQ
250W –75dB 1090.0MHz
