FBI file: UFO, UFO Part 10

Read from the scan by GLM-OCR; expect the odd misread word.

On 10 September 1951 as AN/MPG-1 radar set picked up a fast moving low flying target (act alt undetermined) at approx tely 1110 hours SE of Fort Monmouth at a range of about 12,000 yards. The target appeared to approximately follow the coast line changing its range only slightly but changing its azimuth rapidly. The radar set was switched to full aided azimuth tracking which normally is fast enough to track jet acft, but in this case was too slow to be resorted to. The target was lost in the NE at a range of about 14,000 yards. This target also presented an unusually strong return for an acft being comparable in strength to that usually received from a coastal ship. The operator initially identified the target as a ship and then realized that it could not be a ship after he observed its extreme speed.

On 11 September 1951, 1050 hours, 2 SCR 584 serial nos. 217 and 315 picked up the same target NE of Fort Ronmouth at an elevation angle of 350 to 300 mils at a range of approximately 30,000 yards. (Approximate altitude 31,000 ft) the sets track automatically in azimuth and elevation and with aided range tracking are capable of tracking targets up to a speed of 700 mph. In this case however, both sets found it impossible to track the target in range due to its speed and the operators had to resort to manual range tracking in order to hold the target. The target was tracked in this manner to the maximum tracking range of 32,000 yards. The operators judged the target to be moving at a speed several hundred miles per hour higher than the maximum aided tracking ability of the radar sets. This target provided an extremely strong echo at times even though it was at maximum range, however the echo signal occasionally fell off to a level below normal return. These changes coincided with maneuvers of the target.

On 10 September 1951, 1515 hours, an SCR 584, serial no. 433 tracked a target which moved about slowly in azimuth N of Fort Monmouth at a range of about 32,000 yds at the extremely unusual elevation angle of 1350 mils. (Altitude approximately 93,000 ft)

On 11 September 1951 at about 130 a target was picked up on an SCR 584 radar set serial no. 315 that displayed unusual maneuverability. The target was approx. over Navesink NJ as indicated by its 10,000 yard range, 6000 ft altitude and due N azimuth. The target remained practically stationary on the scope and appeared to be hovering. The operators looked out of the van in an attempt to see the target since it was at such a short range, however overcase conditions prevented such observation. Returning to their positions the target was observed to be changing its elevation at an extremely rapid rate, the change in range was so small the operators believed the target must have risen nearly vertically. The target ceased its rise in elevation at an elevation angle of approx 1500 mils at which time it proceeded to move at an extremely rapid rate in range in a sputterly direction once again the speed on the target exceeding the rided tracking ability of the SCR 584 so that namual tracking became necessary. The radar tracked the target to the maximum range of 32,000 yards at which time the target was at an elevation angle of 300 mils. The operators did not attempt to judge the speed in excess of the aided tracking rate of 700 mph.

CONFIDENTIAL