We thank the referees for their comments.

In response to referee 1 we have incorporated the reviewer’s suggested description of the Arecibo heater status in the first paragraph of section 6.

In the section on conspiracy theories where HAARP is mentioned, we have shortened and re-written that section in a more neutral way, but we did not include the referee’s suggested description of HAARP since we find the details on the history and funding of HAARP not relevant for this paper. That paragraph now reads:

"The Tromsø heating facility has not been overly troubled by adverse publicity or conspiracy theories. The experiments conducted at the Tromsø facility were always open and all publications resulting from it appear in the open literature and we believe this is true for nearly all of the experiments performed at the other facilities as well. Nevertheless, over the years there have been exaggerated and false claims and conspiracy theories made about some of the experiments that are possible with heating facilities like HAARP in Alaska and Heating in Tromsø."

We thank the referees for their comments. 

In response to referee 2, we have incorporated all suggestions made.

Line 35: We believe this form of reference to a whole journal issue is correct.

Line 53: Dipl. Phys. is explained in parentheses.

In line 251, “guy” is indeed correct. Among other meanings it includes: “A rope, cord, or cable used to steady, guide, or secure something. tr.v. guyed, guy·ing, guys To steady, guide, or secure with a rope, cord, or cable. [Partly from Middle English gie, guide, guy (from Old French guie, from guier, to guide; see weid- in Indo-European roots)   (www.thefreedictionary.com)

Line 259: The units of the frequency range were omitted. They have now been inserted.