In this blog, I will try to simulate receiving antennas for MW DX. In these days, Flag antenna and its modification are very popular among enthusiastic MW DXers because these antenna are directional antennas that can mitigate interference from strong domestic MW radio stations on adjacent frequencies. A directional characteristic of typical flag antennas is cardioid.
To conduct the simulation of MW receiving antenna we should know some parameters for electric characteristics of ground. These are conductivity that is reciprocal of electrical resistivity and relative permititivity.
Figure.1 shows the distribution of electrical resistivity of Japan archipelago. The conductivity is the reciprocal of the electrical resistivity. For example the conductivity of orange area in this figure is from 3[mS/m] to 1[mS/m].
Fig.1 Electrical resistivity of Japan archipelago
*This figure is linked to http://www.sankosha.co.jp/technical_data/technical_earthing/daititeikou.jpg
The relative permititivity can be obtained from ITU-R recommendation P.527-3. The relative permititivity for medium dry ground is about 15.
Fig.2 Relative permititivity and conductivity as a function of frequency
From these results, I decided to use these parameters for the simulation as follows.
Conductivity : 1to 3[mS/m]
Relative permititivity : 15