Microwave Moisture Determination of Coal.- A Comparison of Attenuation and Phase Measurement

The major disturbing influences on moisture determination of coal were investigated by measuring the attenuation and the phaseshift of the transmission in a wide frequency range: The influence of bulk density and layer thickness can be eliminated by an additional determination of the weight per area. A comparison of attenuation and phaseshift showed, that the phase measurement is less influenced by salt content, grain size distribution and temperature.