the mode of operation, indicates ground speed and
drift angle, and indicates when the system is in the
search mode.
The signal representing drift angle from the
antenna is fed to the servo follow-up in the indicator
and positions the DRIFT angle dial to the correct drift
angle. The RT develops a voltage proportional to the
Figure 2-16.-AN/APN-153(V) components.
APN-153(V). B. AS-1350/APN-153(V).
APN-153(V).
A. RT-680A/
C. C-4418A/
frequency of the frequency generator, which is then
fed to a servomotor in the indicator. This servomotor
positions the GND SPEED dial to indicate the ground
speed. The mode switch should be set to the LAND
position when the aircraft is overland, and to the SEA
position when over the sea.
With the mode switch in the TEST position, you
should get the following indications after a 1-minute
delay:
l
l
l
MEMORY light is off.
GND SPEED dial indicates 121±5 knots.
DRIFT angle dial indicates 0±2°.
The memory light indicates that the audio from
both radiated patterns is lost. This means that the
system cannot provide accurate information. The two
indicators will be locked at the present readings until
the RT starts to receive good signals.
Q1.
Q2.
Q3.
Q4.
Q5.
Q6.
Q7.
Q8.
Q9.
Q10.
Q11.
REVIEW QUESTIONS
What is the definition of direction?
What is the difference in miles between the
highest and lowest points of the earth's crust ?
What are the imaginary reference lines used
to locate points on the earth called?
What is the definition of absolute altitude?
In the counter-pointer display, how many
revolutions does the pointer make per 1,000
feet of altitude?
What is the reliable altitude range for the
AN/APN-194(V) radar altimeter?
How is the barometric switch in the RAWS
system reset prior to flight?
What are the operating modes of the ADF
system?
What TACAN operating mode ensures that
radio silence is maintained?
What are the three operating frequencies used
in the omega system?
What are the two pieces of data information
provided by the AN/APN-153(V) Doppler
system?
2-19
