LESSON 4 - EXERCISE 2
Complete items 1 through 6.
1. Line-of-sight propagation can be extended to long earth surface
transmissions through the use of ____________________________________ .
2. What mode
of
propagation
is
no
longer
used
for
military
a.
c.
b.
Ionospheric scatter.
d.
Line-of-sight.
3.
Skywave (ionospheric) propagation is affected by day-to-night
and seasonal changes, what must be done to have uninterrupted service
in a fixed point-to-point communications circuit?
a. Use
more
power
(watts)
during
the
hours
of
darkness.
b.
Use space diversity at the receiving antenna field.
c.
Change operating frequency.
d.
Change antenna polarization and height of the antenna.
4.
Waveguide propagation mode occurs below
a.
30 kilohertz.
c.
300 kilohertz.
b.
600 kilohertz.
d.
200 kilohertz.
5. Frequencies below about 50 megahertz and especially below 3
megahertz are used for commercial broadcast and navigation purposes
using surface wave propagation.
a.
True.
b.
False.
6.
What are three factors that determine the separation between two
ground-based terminals using line-of-sight propagation.
a.
___________________________________________________________ .
b.
___________________________________________________________ .
c.
___________________________________________________________ .
Check you answers with the exercise solutions on page 100.
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