1-11.
At what frequencies does the
combination of the earth’s
surface and the D layer act as
a waveguide?
1.
Vlf
2. Lf
3. Mf
4. Hf
1-12.
The D layer loses its
absorptive qualities at
frequencies above what level?
1.
30 MHz
2.
20 MHz
3.
10 MHz
4.
3 MHz
1-13.
What is the approximate range
of the E layer above the
earth’s surface?
1.
30–54 miles
2.
55–90 miles
3.
91–130 miles
4.
131–160 miles
1-14.
Frequencies above what level
pass through the E layer
unaffected?
1.
50 MHz
2.
100 MHz
3.
150 MHz
4.
200 MHz
1-15.
During daylight hours, the F
layer will divide into how many
separate layers?
1.
Five
2.
Two
3.
Three
4.
Four
1-16.
Most high–frequency, long-range
communications occur in what
layer(s) of the ionosphere?
1. D
2. E
3. F
4. H
1-17. Which of the following is NOT a
factor for radio wave
refraction?
1.
Ionization density of the
layer
2.
Frequency of the radio wave
3.
Angle of incidence
4.
Transmitter power
1-18.
For any given ionized layer,
the critical frequency is just
below the escape point.
1.
True
2.
False
1-19.
The critical angle for radio
wave propagation depends on
what two factors?
1.
Angle of incidence and
layer density only
2.
Layer density and
wavelength only
3.
Angle of incidence and
wavelength only
4.
Wavelength and antenna
height only
1-20.
What term best describes the
area located between the
transmitting antenna and the
point where the sky wave first
returns to the earth?
1.
Ground wave
2.
Skip zone
3.
Skip distance
4.
Ace area
1-21. Which of the following factors
will affect the outer limits of
the skip zone?
1.
Frequency
2.
Sunspot activity
3.
Angle of transmission
4.
All of the above
1-22.
Radio waves reflecting from the
earth’s surface or the
ionosphere, 180 degrees out of
phase, have what effect, if
any, at the receiving station?
1.
The signal will be weak or
faded
2.
The signal will be stronger
3.
The signal will be garbled
4.
None
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