Revision A
T-48 90 008 026
2-6
2. Remove and store/dispose of the two fuses.
3. Pull the bottom fuse holder from the rear of the cartridge, rotate, and reinstall back in the
cartridge ensuring that
220
is viewable through the front window.
120
220
Configured for 120 VAC Configured for 220 VAC
Fuse Cartridge
Figure 2-3
4. Replace the fuses with 250V 1/8A, FTT fuses and reinstall the cartridge back in the Fuse
housing.
2.9 Supplied
Antennas
Standard equipment supplied are two (2) antennas to facilitate a variety of tests. An Omni-Directional
Antenna (TSP-1A) and Antenna Coupler (TAP-135) are stored in the T/S cover. The T-48A is equipped
with two (2) TAP-135 Antenna Couplers to facilitate Diversity Testing of dual antenna Transponders.
NOTE
An
OPTIONAL
Direct Connect Coupler (TAP-141) with an attenuated path, to protect the Test Set, may be
purchased separately for direct connection of a transponder receiver/transmitter to the T-48 Test Set. This is
useful to determine and troubleshoot problems by separating the aircraft antennas and cables from the rest
of the system. The TAP-141 also provides the means to accurately measure transponder power, receiver
sensitivity, and frequency.
2.9.1 Omni-Directional
Antenna
The Omni-Directional antenna is stored inside the T-48 cover. This antenna’s primary task is to provide a
quick-test capability for ATCRBS Mode A/C and Mode S equipment. The following suggestions will
improve your overall test results when utilizing the Omni-Directional Antenna. Transponder RF power,
receiver sensitivity, and frequency measurements are not displayed. Utilize the TAP-135 Antenna Coupler
or the
Optional
TAP-141 Direct Connect Coupler for frequency and power measurements.
NOTE
To accurately measure power, receiver sensitivity and frequency, utilize the TAP-
135 Antenna Coupler or direct connect to the transponder with the
OPTIONAL
TAP-
141 Coupler. The Omni Directional antenna is used for a QUICK check of the
system only. Power, Frequency, and Receiver Sensitivity are not displayed when
using the Omni Antenna.
