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)).
This recommendation replaced the original broadcasting propagation prediction curves given in Recommendation ITU-R P.370. The adjusted P.1546 model is suitable for modelling propagation path loss in the broadcasting, land mobile and certain fixed services (e.g. those employing point-to-multipoint systems) in the frequency range 30 to 3 000 MHz and for the distance range 1 km to 1 000 km.
A few simplifications have been introduced for SEAMCAT implementation of the model:
- Restriction to propagation over land paths only;
- Flat terrain;
- No negative antenna heights.
Figure 477: SEAMCAT Interface to the ITU-R P.1546-1 propagation model
Table 86: ITU-R P.1546-1 propagation model
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 |
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.