11.3.7 Clutter Loss

We have now accounted for the three largest sources of loss in radio path free-space, reflection, and diffraction loss. Clutter loss is an additional path loss that results from diffraction and scattering of the radio wave in the immediate surroundings of the transmit and receive antennas. In fixed systems, adequate siting can significantly reduce this loss but mobile systems are normally constrained in the location of antennas as a ground vehicle moves through wooded areas or by the space constraints that exist on aircraft and ships.

The only way of accurately determining the clutter loss for a particular site is by empirical measurement. This is relatively straightforward for ships and aircraft where clutter loss is constant since the antenna location is fixed. In these cases, the clutter loss would normally be measured and then incorporated in the system value as a constant for that configuration. However, in field systems the location of the antenna will vary with each deployment, and the clutter loss is normally determined from a graph of typical losses for the type of terrain that surrounds the antenna. Clutter losses must be added for each end of the link.