Evaluation of night errors in aircraft direction finding 150-1500 kilocycles

An elementary account of the production of night errors in a m.w. direction-finder located on the ground or at a height above the earth's surface, through the simultaneous presence of (a) the direct wave, (b) the sky wave and (c) the sky wave reflected from the ground. The variation of the bearing as an aircraft moves through the complex field resulting from reflections from the E-layer or from a mountainside, is studied for the case of an aircraft using a spinning loop radio-compass. Rules are formulated for the correct interpretation of radio-compass indications.