Figure 3-5.—Control monitor front panel.
radar, it can accommodate rotation rates from 2 to 30
rpm, receiving radar synchro information via the
radar switchboard. In the manual mode, it can
position the antenna to any azimuth directed from a
remote position. The antenna pedestal assembly can
mount the AS-2188( )/UPX or any other 10-foot
antenna designed to mount on the same platform. The
pedestal disconnect mast switch, located above decks,
removes all power from the pedestal assembly.
The selection of system antenna equipment
depends on which radar is using the Mark XII system.
For installations where the rotary joint will not pass
the switching bias, the AS-2188( )/UPX will transmit a
sum pattern only, with a separate AS-177( )/UPX
omnidirectional antenna transmitting the difference
rf. Some installations use an integral antenna to
transmit and receive both radar and IFF signals, with
difference rf transmitted on a separate AS-177( )/UPX
antenna.
TRANSPONDER SECTION.—The transponder
receives interrogation pulses and, in turn, generates
the proper reply pulses. A simplified block diagram of
a typical shipboard transponder section is shown in
figure 3-6. As we discussed before, desired reply codes
are set by thumbwheel switches for modes 1, 2, and
3/A; ships are wired for code 0000 mode C replies.
Mode 4 replies are coded automatically according to
the crypto key installed in the TSEC/KIT-1A.
The organizational-level maintenance of the
Mark XII IFF system is performed by ETs (NEC ET-
1572). You must have formal training or written
permission from your commanding officer to work on
the TSEC/KIR-1, TSEC/KIT-1, or TSEC/KIK-18
crypto units.
The AIMS Newsletter, published by Naval
Electronic Systems Engineering Activity (NESEA) St.
Inigoes, Maryland, provides information to shipboard
technicians and operators on AIMS systems, primarily
Mk XII IFF and its related subsystems. It keeps you
up to date on any equipment modifications, PMS
changes, and significant interface problems. It also
gives you an AIMS hotline number to use if you have
any questions or problems concerning maintenance or
operation of Mk XII IFF equipment. You can find
more information on this publication in ET, Volume 2,
Administration.
Agreements between the Navy, Air Force, and
FAA, under the AIMS program, required the
development of a system to present ATCRBS data
instantly, in symbolic and numeric form, directly on
the indicator, and superimposed over live radar video.
The AIMS Mark XII IFF system does this for ships.
Under the AIMS
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