he GPS. A straight line is then drawn on the map and points at each kilometre are marked on this line. The surveyor then drives along the marked line (as much as possible), goes to each of these points to verify the height above the average mean sea level (AMSL) and cross checks with the map. A check is also mede to see whether there are any obstructions that might not be marked on the map. Then these actual AMSL readings are put in a software tool (or mathematical formulas are simply used, which are given elsewhere in the chapter) to find what minimum antenna heights will be needed to achieve the desired clearance. The creation of the profile is explained in the next subsection. The engineers/surveyors should, however, go through tower climbing training before they climb high towers. The outcome of the LOS survey is an LOS report that clearly marks whether there was an LOS or no LOS. Apart from this, the report consists of 360° photographs, feeder lengths (optional), exact location and minimum height of the microwave antenna(s), hop bearing and distance, future possible obstructions (photographed or listed), type of tower, mast or pole to be used, etc. Path Profile The path profile is a graphical representation of the path between the transmitting and receiving antenna sites. The path profile in conjunction with the fresnel zone calculations helps to define the antenna heights. Also, antenna heights can be adjusted based on the path profiles in order to avoid obstructions, reflective surfaces, etc. Microwave Link Planning Table 3.9 Measurements for a path profile Distance [km] Terrain height [m] There are mainly three methods used to draw a path profile: 1. Fully linear method 2. 4/3 earth method 3. Curvature method Of these three, the fully linear method is the one recommended SO it will be discussed in detail here. Fully Linear Method This method is the recommended method because it is possible to represent many variations of the k- factor on one chart, apart from the fact that simple linear graph paper can be