Hello, The V056 was NEVER equipped with the full radar installation but only used for test of various types of antennas. Mainly was tested the standard rod type and then as on the photo the "profiled" type, to establish the characteristics especially the loss of speed. The rod type had an effect on the speed in the range of 65-70 km/h where the profiled was in the range less than 20 km/h, but had problems in handling forces from the side like experienced in a x-wind landing or side slipping.
The tests was carried out in February-March 1945.
The antennas was meant for the production variant of the ME262 night fighter, the B-2 that was in the final prototype stage in march 1945. (maybe one airframe finished by the end of march)
The antenna seen on the B1-a/U1 was the standard rod type developed by Siemens.
And NO the V056 was NOT the personal aircraft of Kurt Welter