Document from the year 2015 in the subject Engineering - Communication Technology, , language: English, abstract: This work is the result of curiosity and interest in technology. At first, it was an accidental discovery in 2001. This led to the desire, to learn more about ELF-signals. For that, it was necessary, to develope an inexpensive and widely available receiving-technology. The result is an ELF receiver technology, which includes hardware and software. It is designed with standard parts, which are low in prices and easy to get. Any standard PC with an USB connector and a sound card can be used for detection and analysing.My research and development was operated part-time and now covers more than 10 years. With writing of these theses in the first version, I started in October 2008.