Ideally, the power transmitted in a dual polarization weather radar system would be independent of the polarization mode. However, this is not the case due to separate waveguides, couplers, feedhorns, and differences in antenna gain due to polarimetric orientations. A correction factor, the Zdr offset is used to compensate for these differences. This paper reviews the advantages and disadvantages of several Zdr offset measurement techniques. In addition, we discuss the difficulties associated with obtaining an accurate estimate in a well-matched system .