Difference between revisions of "Fade Mechanisms"
From PathlossWiki
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|0.088 | |0.088 | ||
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| + | Link Performance Definition | ||
| + | The definition of link performance only considers multipath and rain fades. | ||
| + | This implies the following assumptions: | ||
| + | |||
| + | * the path has sufficient clearance / fade margin to obviate the possibility of an obstruction fade. | ||
| + | * signal nulls due to a specular reflection are small com-pared to the fade margin or a space diversity configura-tion has been implemented. | ||
| + | * the probability of ducting is unknown. | ||
Revision as of 14:25, 21 February 2020
Microwave fades fall into the following categories:
- Multipath fading
- Obstruction fading
- Fading due to a specular reflection
- Ducting and propagation anomalies
- Rain fading (above ~ 8 GHz)
With the exception of rain fading, microwave fading only depends on the change of the refractive index with height along the path
| Availability | Seconds | Minutes | Hours |
|---|---|---|---|
| 99% | 315360 | 5256 | 87.6 |
| 99.9% | 31536 | 525 | 8.76 |
| 99.99% | 3153 | 52.5 | 0.876 |
| 99.999% | 315 | 5.3 | 0.088 |
Link Performance Definition
The definition of link performance only considers multipath and rain fades.
This implies the following assumptions:
- the path has sufficient clearance / fade margin to obviate the possibility of an obstruction fade.
- signal nulls due to a specular reflection are small com-pared to the fade margin or a space diversity configura-tion has been implemented.
- the probability of ducting is unknown.
