One may never say never on this kind of thing, but U-166 carefully reported her successes and positions in the last weeks before she was sunk.

She sank a very small motor boat (gunfire and/or hand grenades) on July 1942 just northwest of Cuba, then reported a position south of Cuba for the next few days. Then she reported a direct course from west of Cuba into the Gulf and direct to the mouth of the Mississippi River, where she patrolled in the local area for about 5 days before sighting and sinking the "Robert E Lee", a steamer on it's way to New Orleans; a small "sub chaser" vessel escorting the Robert E Lee counter immediately attacked and sank U-166 with all hands.

It's pretty clear that U-166 concentrated on the shipping lanes leading to the Mississippi when in the Gulf. But her radio was designed to communicate with the b-Dienst stations in Germany and coastal France - it's certainly possible that a local radio ("ham") listener in Pensacola could have picked up signals from U-166. I think that the real issue is whether an attack on U-166 by an aircraft could have been seen from Pensacola. Just as a general guess, this seems unlikely; one would have to look carefully at the U-166's reported positions in the days before her sinking and get a documented account of such an attack (date, time, location, etc.) to have any evidence of this coincidence. Also, what are the usual currents in the coastal central Gulf like? (I live in coastal North Carolina and I would understand that clothes from a craft lost at sea near Myrtle Beach SC might wash ashore at Hatteras three days later - but I'm not familiar with what you'd expect there.) And, Dr. Axel Niestle surmises that an aircraft attack once thought to be against U-166 was against U-171 so he must know evidence that U-171 was in the area.

So, I think you have three questions 1) was the radio signal from U-166? (Possibly) 2) was the aircraft attack near Pensacola against U-166? (Unlikely) 3) Were "American style clothes" washing ashore near Pensacola from U-166? (Also possible, but unlikely)

Not saying, "definitely not" but unlikely (in my opinion).