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	A17.78.1
	A17.78.1

This is a point-to-area propagation loss model. There are three implementations of this recommendation in SEAMCAT (Recommendation ITU-R P.1546-1, ITU-R P.1546-4, and ITU-R P.1546-5 (see the next two sections)).

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Restriction to propagation over land paths only;
Flat terrain;
No negative antenna heights.

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	F471F477F471
	F477

Figure 471477: SEAMCAT Interface to the ITU-R P.1546-1 propagation model

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	T084T086T084
	T086

Table 8486: ITU-R P.1546-1 propagation model

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Description	Symbol	Type	Unit	Comments
Variation

				Variation in path loss
General environment

				Environment of the propagation: urban, rural, suburban
System

				Digital (BW<1MHz), Digital (BW>1MHz), Analogue
Time Percentage (min)

			Minimum time variability from which the field strengths value are exceeded
Time percentage (max)

			Maximum time variability from which the field strengths value are exceeded
use user specified local clutter height

User selectable clutter height value which overwrite any predefined value when selected

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This propagation model is described in Recommendation ITU-R P.1546-1 Annex 8, which was developed based on the prior model in Recommendation ITU-R P.370. This is a propagation model for point-to-area prediction of field strength for the broadcasting, land mobile, maritime mobile and certain fixed services (e.g. those employing point-to-multipoint systems) in the frequency range 30 to 3000 MHz and for the distance range 1 km to 1000 km. The model provided in Recommendation ITU-R P.1546-1 should be used in the frequency range (30 to 3 000 MHz) and the same distance range (1 km to 1 000 km). The Land curves are implemented only. The sea curves or the mixed sea-land path are not implemented.

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Old Version 4

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