Friederike

Encoding or decoding random radio-waveforms doesn't need incredible expensive hardware anymore which offers new possibilities for building up over-the-air communication systems. There are Software Defined Radios providing affordable cellular radio to remote villages, Community Radios are using SDR to build up digital radio networks and other cool stuff. Some basic knowledge what is going on in SDR Hard/Software as the influence of the samplerate, I/Q-data of the math behind the waterfall-diagram is helpful to have fun with SDR. Some theory on modulation techniques helps you to decode or encode your waveforms.

With a cheap DVB-T USB receiver used with some SDR-Software you can already have a look whats going on in the airwaves around you at certain frequencies. But what happens between the antenna and your computer display showing or decoding the signal? The talk should give basic information and background about SDR and some modulation theory. There will probably be a SDR Challenge at the Congress to practice you new skills.

Maxwell's equations are four differential equations which form the foundation of classical electrodynamics, classical optics, and electric circuits. This talk will take a look at the connection between these equations, wave propagation and antenna arrays.

Maxwell's equations describe how electric and magnetic fields are generated and altered by each other and by charges and currents. They are named after the Scottish physicist and mathematician James Clerk Maxwell, who published those equations exactly 150 years ago and form the foundation of classical electrodynamics. Actually Maxwell had 20 equations and it took another 20 years until they were understood and the self-taught British engineer, mathematician, and physicist Heaviside put the equations in their present form. Some years later Hertz brought the experimental prove of Maxwell's theory. Under a lot of simplifying boundary conditions wave propagation and antenna theory can be derived from this four equations. This talk will lead from Maxwell's equations to wave equations and nice antenna forms and arrays. Also some practical aspects will be evaluated. Why do low frequencies reach farther than higher frequencies? Why do radio astronomers spread their antenna arrays over whole continents? Or why is China Mobile building antenna arrays for mobile radio consisting of 128 antennas?