12.7.4 Alignment Of Sky-Wave Antennas

The alignment of sky-wave antennas is determined by a number of factors, including the radiation pattern, the space available, and the effect of the Earth’s magnetic field. For short ranges, where the wave is going straight up and down again, the alignment does not matter, except in the tropics where antennas should be aligned north-south irrespective of the direction of working. Dipoles greater than a quarter wavelength above the ground should be broadside on to the direction of working. For distances greater than 1,000 km, a great circle bearing must be used to align directional antennas—failure to do this may result in an error of 10˚ or more.