Accuracy Analysis of the Millington's Prediction Method in the Medium Waveband

Abstract

Millington's field strength prediction method is analyzed under different simulation conditions on the basis of the results of a medium waveband (MW or medium wave band extends from 530 to 1600 kHz) digital radio mondiale (DRM) measurement campaign. Millington technique applies the reciprocity condition by simply averaging the forward and reverse field strength values. This simplified approach could be a source of field strength prediction error in the MW planning tools. Critical path features for the fulfillment of the reciprocity condition are identified and their influence on predicted values is stated. Reciprocity effect on the predictions error is evaluated by means of the difference between digital medium wave field strength measured values of certain critical selected paths, and the corresponding Millington's method predicted ones. It has been found that the prediction error can be as high as 15 dB when comparing Millington's method results and measurements but the simple reciprocity approach made by Millington procedure is not the most remarkable source of error.Index Terms-Digital radio mondiale (DRM), field strength prediction, ground wave, medium wave, Millington's method.

2DE-WAVE Tool for Computing Theoretical Field Levels at MF & HF band and Comparison with Experimental Values in a Real Environment

“…It is known that, by definition, the Millington method is based on the reciprocity method [40], which makes a weighting of the E field calculated in the direction from Tx to Rx and reversing the procedure from Rx to Tx; depending on the circumstances, this approximation may be more or less accurate, and large differences between the direct and the reverse paths can exist.…”

“…We can also stress that the more different the change between adjacent sections is, the higher the difference between E TxRx and E RxTx will be. If the variations of conductivity values tend to offset themselves (in one case, a positive increment, and in the next, a negative increment), the difference between the direct and reverse paths tends to be reduced [40].…”

“…It is necessary to note that there are previous studies that stress the influence of conductivity changes and topographical irregularities [38][39][40] on field values; in this paper, unlike them, we implement a software application that automates the calculation of electric field values for a flat area of interest in two dimensions. It also creates interpolated field value maps, which give an overview of the distribution of field levels in the area in question.…”

“…It is important to note that there are also various studies that explore the importance of calculating the surface impedance, the influence of the type of surface, and the implication of conductivity changes in the different sections when using the Millington method [40][41][42].…”

Antenna Radiation Efficiency of the Korean NDGPS Based on Radiation Power Measurements

“…Then, the radiation efficiencies for the Korean DGPS of (1) are deduced by comparing the measured data and theoretical data. The conductivity data of the Korean territory is used in (7), which is shown in Fig. 3.…”