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A17.2 A17.2

This model describes the theoretical minimum propagation path loss achievable in free space conditions. This model is appropriate to use on paths were unobstructed direct-Line-of-Sight propagation could be expected (e.g. point-to-point fixed service links, links over short distances in open areas, etc). 

 

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Figure 465470: SEAMCAT Interface to the free space propagation model

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For free space {XE "Propagation model:Free space" } model the path loss is defined by: 

(correct EQ to be inserted)

                                             (Eq. 180189)

The variations correspond to the standard deviation variations.

Note: The Free space model allows the possibility to include some variations in the similar manner as it is done for all other built-in models. If user wants to use just the median theoretical value, the variations option should be disabled.

Figure 466 471 illustrates when the variation is disabled (i.e. no std).

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Figure 466471: Example of the vector events of the Free Space when Variation is disabled
(i.e. equivalent to σ = 0 dB) active (i.e. mean = 91.52 dB)

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Figure 467 472 presents the Free Space when Variation is activated (std = σ = 2.5 dB). The value presented in Figure 466 471 and Figure 467 472 are extracted with the following parameters: f = 900 MHz, d =  1 km, h_tx = h_rx = 10 m.