Handbook of Propagation Effects for Vehicular and ... - Courses

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8.4.3 Distance and Frequency Dependence
Propagation Effects for Vehicular and Personal Mobile Satellite Systems
Figure 8-14 shows an example describing the relative signal level versus position at four
frequencies extending over approximately 1 GHz to 3 GHz for the Commons. We note
the relative signal varies between -15 to -30 dB for scenarios in which the direct path
penetrates a concrete wall (e.g., 0 to 3 m). It increases to the range of -5 to +5 dB as the
antenna moves across the window area and ends up outside the open door (e.g., 4 to
5.5 m). By contrast, an extreme case is depicted in Figure 8-15 for the House that shows
levels ranging from -25 dB to -45 dB. These low fade levels are presumed to occur
because the construction includes a metal roof and a tight energy conserving aluminum
heat shield under the cedar exterior.
Relative Level (dB)
5
0
-5
-10
-15
-20
-25
-30
-35
-40
-45
2093 MHz
2992 MHz
0 1 2 3 4 5 6
Distance (m)
1023 MHz
1463 MHz
Figure 8-14: Relative signal level versus position at four frequencies in the Commons.