Radio astronomy can be recorded and pieced together in a mosaic image. The type of instrument used depends on the strength of the signal and the amount of detail needed. Observations from the Earth's surface are limited to wavelengths that can pass through the atmosphere. At low frequencies, or long wavelengths, transmission is limited by the ionosphere, which reflects waves with frequencies less than its characteristic plasma frequency. Water vapor interferes with radio astronomy at higher frequencies, which has led to building radio observatories that conduct observations at millimeter wavelengths at very high and dry sites, in order to minimize the water
Atmospheric-pressure plasma earth potential and in this way largely holds back potential-carrying parts of the plasma stream. In addition, it determines the geometry of the emergent beam. Based on transistor amplifiers up to 200W power RF (radio frequency) and microwave sources are used to generate a microwave plasma. Most of the solutions work at 2.45 GHz. Meanwhile, is a technology developed which provide the ignition on the one hand and the high efficient operation on the other hand with the same electronic and couple network. This kind of atmospheric-pressure plasmas is different. The plasma is only top of the electrode. That is