Revision A
T-48 90 008 026
2-12
2.11.2 Mode 3A/C Manual Sequence of Transponder Tests
To manually display each test performed by the Test Set, the operator must select and press the
TEST
switch. The T-48 will then run each test in order (Figure 2-6) but pause and display the results of each test.
The operator must then depress the
TEST
button again to proceed to the next test in sequence.
TEST
button depressed.
MODE 3A Test Initialized.
MODE 3A Test Complete. Display indicates transponders 4096 Octal
Code (1234) and Receiver Efficiency (100%) as a percentage. Framing
Pulse Widths and Spacing are also tested. Refer to paragraph 2.12 for
further information.
To check the transponder under test “
IDENT
” function. Press the appropriate button in the aircraft or on the
test fixture. Toggle the
STORE/REPEAT
switch on the T-48. The MODE 3A test will commence and the
display will indicate “
IDENT
”, verifying the
SPI
pulse was received.
“
IDENT
” signal received.
The
TEST
switch must then be pushed once more to proceed to the next test.
MODE 3C Test Initialized.
Mode 3C Test Complete. Display indicates the reported aircraft altitude
(to the nearest 100 ft.) and receiver efficiency as a percentage. Pulse
width and spacing measurements were also performed.
TEST
button depressed to proceed to the final Mode 3A/C Transponder Test.
Transponder
power,
receiver efficiency, and frequency test initialized.
Test Set measures transponder RF output (54dBm), Receiver Sensitivity (-75dBm), and Frequency (1090.0
MHz). Second alternating page displays power as watts (250W).
MODE 3A/C XPDR
INTERROGATE TO TEST
MODE 3A & SLS
TESTING . . .
MODE 3A
1234 100% REPLY
MODE 3C
TESTING . . .
MODE 3C
10,000FT 100% REPLY
POWER, RCVR & FREQ
TEST
POWER, RCVR & FREQ
54dB–75dB 1090.0 MHz
MODE 3A IDENT
1234 100% REPLY
POWER, RCVR & FREQ
250W–75dB 1090.0 MHz
