Communications, Radar & Electronic Warfare (201.. - Index of

Planning Radio Networks for CoverageI \side View]AntennavIAntenna tilt\ljl t:: :1 ------------------. -+ :Antennab±:lncreased antenna lilt241side vie: :11-------------II111111Coverageplan viewCoverageplan viewCoverage withIncreased tiltOnglnalcoverageFigure 13.10Effects of antenna tilt changes.the emphasis on systems working in an electronic warfare environment where there is aneed to avoid detection, interception, localisation and jamming. In essence, we wish tobe able to use a communications system while minimising vulnerability by reducingthe energy available to the enemy and reducing incomingjammjng energy from enemyjammers. We can do this by a number of different means, all of which require anunderstanding of the operational picture and the relative positions of our owncommunications and enemy assets. However, it is not necessary to have localisedenemy assets, although if possible this is desirable.The first potential method is to use terrain as a deliberate shield against the enemy.Figure 13. 12 shows an illustration of a scenario where the enemy is to the North, with aline of demarcation (Forward Edge of the Battle Area [FEBA]) shown as a straight linerunning across the terrain. In this case, we can see a range of hills which we can use forterrain shielding. These are shown towards the East side, with the dark areas showingsteep south-facing slopes. These are facing directly away from the enemy side,wherever enemy assets are placed in this area.If we examine a path from our own side to the enemy side as illustrated inFigure 13.13, we can look at the terrain along the path.This is shown in Figure 13. 14. Here we have positioned a transrilltter on the southfacingslope fairly close to the FEBA. The intention of this transrilltter is to providecoverage to the West, East and South but little to the North. The two hills provideshadowing to the north, including a dip within our own territory. However, fromthe perspective of the enemy side, the energy radiated from the transrilltter is shieldedby the terrain.