The field strength contour on this map represents an average value of 0.1mV/m with the E.R.P. indicated; variations of as much as 3:1 in field strength may have occurred at individual points. The  contour should not be interpreted as a rigid boundary of the area served, since the quality of reception obtainable would have depended on local conditions. Fading and interference may at times have been experienced in the outer areas served and also, in difficult locations, nearer the transmitter.