This is the point-to-area propagation loss model. There are two implementation of this recommendation in SEAMCAT (ITU-R Rec.P.1546-1 and ITU-R Rec.P.1546-4 (see next section)).
Recommendation ITU-R P.452-14 contains an interference prediction procedure for the evaluation of the available propagation loss over unwanted signal paths between stations on the surface of the Earth for frequencies above about 0.1 GHz, with losses not exceeded for time percentages over the range 0.001 ≤ p ≤ 50% and up to a distance limit of 10 000 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 471: SEAMCAT Interface to the P1546-1 propagation model
Table 84: ITU-R P.1546-1 propagation model
Description | Symbol | Type | Unit | Comments |
Variation |
|
|
| Variation in path loss takes into account the uncertainty of building design, furniture, room size, etc. |
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.