Copyright © Klaus Piontzik  
German Version 
Now the previous considerations allow a first calculation of a wave that builds up, as the earth, around a sphere. Still, it must be considered that the wave propagation takes place linear and not along the curved surface of the ball. 
After the HuygensFresnel
principle the points A,
B, C serve so as source points of the standing wave (blue) Electromagnetic waves propagate spherically from one point. (red) If point B is the starting point so the distance BDC = h is the way of the wave. 

Illustration 2.4.1 – wave propagation 
Because there is a stationary state, it is sufficient to look at the way of the wave from one source to the next source. 
This makes 
The triangle of MCD in the picture 2.4.1 is rectangular in the point D and apply: 
Shift the equation to h: 
Since now all sizes are known, the wavelength can be determined: 
2.4.1  Equation: 
In the equation is R
the radius of the Earth, n is the number
of waves. This results in the frequency equation for basic oscillations 
2.4.2  Equation:  n = 1,2,3,4,... 
The basic frequency is for n = 1: 
2.4.3 
Equation: 

Illustration 2.4.2 – basic oscillation 
This is also the oscillation of a bar with free ends, which length is equal to the diameter of the ball. 
200 sides, 23 of them in color 154 pictures 38 tables Production und Publishing: ISBN 9783735738547 Price: 25 Euro 
