APX (fig. 16), or equivalent, (one required)
ponents, the antenna connector, and the pres-
is needed to receive the signal of the interrogat-
ing station and to radiate the reply signal.
b. The MT-3809/APX-72 (fig. 1-4) is a
hard-type mount. It has a recess at the rear
b. Control, Transponder Set C-6280(P)/
into which a protruding lip on the RT859/
APX. The C6280(P)/APX (fig. 1-7) (one re-
APX-72 lower case is placed. Two swivel oper-
quired) is needed for operation of the RT-859/
ating nut and bolt combinations at the front
APX72. The C6280(P)/APX applies power
fasten down on two protruding feet on the
to the RT-859/APX72, determines the modes
front of the RT-859/APX-72. The MT-3809/
and categories of operation, and selects the
APX-72 is constructed of caste aluminum.
mode code settings except for mode 2. Refer to
manual NAVWEPS 16-35C6280-1/T.O. 12P4
c. The MT-3948/APX-72 (fig. 15) is iden-
2APX142 (Navy/Air Force) or TM 11-5841-
tical to the MT-3908/APX-72 except for the
addition of four isolators which are connected
to the four corners of the mount.
c. Computer KIT1A/TSEC. The KIT-1A/
TSEC (classified), or equivalent, is required
1-8. Additional Equipment Required
for mode 4 operation of the RT-895/APX-72.
The KIT-1A/TSEC processes mode 4 interro-
The following equipment is not supplied as
gations and prepares the coded reply for trans-
part of the RT-859/APX-72 and MT-3809/
APX-72 and MT-3948/APX-72 but is needed
for partial or full operation of the set:
d. Pressure Altitude Digitizer CPU-66/A.
The CPU66/A, or equivalent, is used in mode
a. Antenna AT-884A/APX. The AT-884A/
Figure 1-7. Control, Transponder