select which signal goes to which pen on the recorder.
The MAD AUX POWER-OFF switch supplies
primary ac power to the SAD system and the selector
control subassembly. The INHIBIT light indicates an
inhibit signal from the SAD system.
MX-8109/ASA-71 SELECTOR CONTROL
SUBASSEMBLY. The MAD signals from the
MAD control and the SAD mark from the MAG VAR
indicator are routed to this subassembly. The selector
control panel selects which one goes to which pen,
and the subassembly routes the signal to the proper
pen. A SAD mark 1-kHz tone is generated by the
subassembly to be supplied to the ICS system for the
RO-32 MAD Recorder
The RO-32 recorder makes a hardcopy of MAD
contacts and SAD marks. This recorder has two
styluses, one black and one red, to differentiate
between the two. The chart drive is removable to
enable the operator to remove and replace the paper
tape. here are three knobs on the faceplate. The first
switch is the ON/OFF switch. The second controls
the intensity of the internal lights. The third knob
selects the operate mode along with the pen
When B is selected on the mode knob, the black
pen should trace along the zero line on the paper tape.
When the mode knob is switched to the +, the black
pen should go to +4. When this knob is switched to
the R position, the red pen traces along the zero line.
When it goes to the +, the red pen should swing to the
+4 line. Both pens are adjustable to these settings.
Learning Objective: R e c o g n i z e t he
classifications and the operating principles
of sonobuoys currently in use.
The detection, localization, and identification of
submarines is the primary mission of the Navys
airborne ASW forces. The ability of the Navy to
complete this mission is dependent upon the
sonobuoy. The sonobuoy has undergone a great deal
of change in the past 25 years. These improvements
have provided the fleet with large numbers of very
reliable sonobuoys that perform various missions.
The sonobuoys are dropped from the aircraft into
an area of the ocean thought to contain a submarine.
The pattern in which the sonobuoys are dropped
usually involve three or more buoys.
The sonobuoys detect underwater sounds, such as
submarine noise and fish sounds. These sounds
modulate an oscillator in the RF transmitter portion of
the sonobuoy. The output of the transmitter is a
frequency modulated VHF signal that is transmitted
from the antenna. The signal is received by the
aircraft, and then detected and processed by a
sonobuoy receiver. By analyzing the detected sounds,
the ASW operator can determine various
characteristics of the detected submarine. The use of
several sonobuoys operating on different VHF
frequencies in a tactical pattern enables the ASW
operator to localize, track, and classify a submerged
Each sonobuoy type is designed to meet a specific
set of specifications that is unique to that particular
sonobuoy. Even though different manufacturers, the
specifications and operational performance
characteristics are the same for all manufacturers.
There are differences in the methods used for
prelaunch selection of life and depth settings from one
manufacturer to another for the same sonobuoy types.
These differences are found in the Sonobuoy
Instruction Manual, NAVAIR 28-SSQ-500-1. You
should refer to this manual prior to storing, handling,
or disposing of sonobuoys.
Sonobuoy Frequency Channels
Certain sonobuoy designs are equipped with an
electronic function select (EFS) system. The EFS
system provides each sonobuoy with a selectable
EFS also provides each
sonobuoy with 50 life and 50 depth setting selections.
The operator must reset all three settings any time any
of the three are changed.
With the older type of sonobuoy, the transmitter
frequency is preset at the factory. here were 31
different channels used within the 162.25- to
173.5-MHz band. Transmitter frequency is designed
to be within ±25 kHz. temperature extremes in hot or
cold storage adversely affect these tolerances,
especially in sonobuoys that are older.