The disclosed method involves using a radio frequency sensor to estimate soot load in a diesel particulate filter. An engine control module receives a first mean attenuation value derived from attenuation values for a set of radio frequencies within a specific band detected by the sensor. Additionally, first standard deviation data related to the mean attenuation value is received. The method determines whether this standard deviation data exceeds a predefined threshold. If not, the first mean attenuation value is used to infer the soot load. If the standard deviation data threshold is exceeded, a second mean attenuation value from a different set of radio frequencies within another band is obtained. Similarly, second standard deviation data is received. If the second standard deviation data does not exceed the threshold, the second mean attenuation value is used to infer the soot load.