We present an improved method to determine the antenna factor of three antennas. Instead of using a reflecting ground plane we use absorbers. Destructive interference between the direct beam and the residual reflected beam from the absorbers is avoided by splitting the measured frequency range in bands and changing the distance between the two antennas depending on the frequency band. Furthermore, this method is applicable for both E- and H-field probes. Our method has also the advantage of being low-cost: the method does not need to be performed in an anechoic chamber to obtain high accuracy. To take the residual reflections of the environment into account, we perform a de-embedding procedure. We have developed two de-embedding methods.