1-33.
During the 27–day sunspot
cycle, which ionospheric layer
experiences the greatest
fluctuations in density?
1. D
2. E
3.
F1
4.
F2
IN ANSWERING QUESTIONS 1–34 THROUGH
1-38,
SELECT FROM THE FOLLOWING LIST
THE DEFINITION OF THE INDICATED TERM.
A.
Depends on the angle of the
sun; refracts hf waves
during the day, up to 20
MHz,
to distances of 1200
miles;
greatly reduced at
night
B.
Reflects vlf waves for
long–range communications;
refracts lf and mf for
short–range communications;
has little effect on vhf
and above;
gone at night
C.
Density depends on the
angle of the sun;
its main
effect is absorption of hf
waves passing through to
the F2 layer
D.
Provides long-range hf
communications; very
variable;
height and
density change with time of
day,
season, and sunspot
activity
E.
Structure and density
depend on the time of day
and the angle of the sun;
consists of one layer at
night and two layers during
the day
1–34.
D layer.
1. A
2. B
3. C
4. D
1-35.
E layer.
1. A
2. B
3. C
4. E
1-36.
F layer.
1. B
2. C
3. D
4. E
1-37.
F1 layer.
1. A
2. B
3. C
4. D
1-38.
F2 layer.
1. A
2. C
3. D
4. E
1-39.
During periods of maximum
sunspot activity within the
eleven-year cycle, critical
frequencies for all layers
increase.
1.
True
2.
False
1-40.
Which of the following problems
is NOT a negative side effect
of the sporadic E layer?
1.
Causes increased multipath
problems
2.
Provides additional
absorption
3.
Blanks out more favorable
layers
4.
Increased static in line of
sight communications
1-41.
When sudden ionospheric
disturbances (SID) occurs,
which ionospheric layer is
affected the most?
1. D
2. E
3.
F1
4.
F2
1-42.
What effect do ionospheric
storms have on (a) the range of
frequencies and (b) the working
frequency used for
communications?
1.
(a) Increase (b) increase
2.
(a) Decrease (b) decrease
3.
(a) Increase (b) decrease
4.
(a) Decrease (b) increase
4
