50ft call is at 50ft Rad Alt. Based on the antenna position and body angle the gear will often be lower, as you can see from the picture in the previous post. In my airplane around 25ft lower.
If the 50-call occurs at the exact moment the antenna is 50 ft off the ground, the lowest point of the landing gear would be at 25 feet. Yet touch down occurs as the radio altimeter reads 0. Something doesn't add up in my head......