TM65 m radio telescope microwave holography

Microwave holography is a valuable technique used in the diagnostics and adjustment of large antennas. A brief outline of the technique is given first. Then detail simulations for surface deviation and sub-reflectorr offsets solving method that applied on the TianMa 65 m are described. After several rounds of adjustments, a reflector surface accuracy 0.28 mm and repeated measurement error 0.13 mm were achieved for the TM65 antenna. At last the antenna efficiency on Ka band was measured at elevations between 45 and 60 degrees. The efficiency improved from 37% to 56% when the active surface model is loaded that is consistent with the theoretical predictions.