The Germans captured a significant number of VT fuses in the Battle of the Bulge which caused the US to develop a jammer based on the AP-4. They quickly produced 200 of them. Were they designed to be used on the ground against air burst VT shells kind of like the first force field? If so how effective would they have been given the fact that the fuse was designed to burst in the air before it hit the ground? How far out could the jammer have made the shell explode and would this have been a significant distance compare to where the original distance was set? Would not the shell be coming in at a high trajectory so the jammer would have to have quite a range to make a difference. How far above the ground did the VT shell typically explode?