Dear Dr Toledo,

I received the answers from two reviewers and they both acknowledge the changes and improvements in the revised version.

Reviewer #2 has still some major concerns related to the calibration target, consistency of units, and antenna alignment. Reviewer #2 also provides a number of suggestions how to solve these issues which I would like to ask you to consider. As this is a technical paper addressing the very important issue of radar calibration, I think it is very important to solve all technical unclarities before final publication. In order to allow reviewer #2 to review again a revised version of the manuscript I decided for major revision. However, I hope that the concerns raised should be solvable in a reasonable amount of time.

Kind regards,
Stefan Kneifel

Dear Dr Toledo and Coauthors,

I am now in receipt of the review of your revised manuscript. Fortunately, most of the technical questions regarding correctness of formulas and units could be solved and I really appreciate the intensive discussion! As you can see in the reviewer comment, there is still concern about the correctness of Eq. 2. The reviewer has again put a lot of effort to explain his concerns but I believe that a convergence can be reached very quickly.

Kind regards,
Stefan Kneifel