The Kassel Dowsing Test provides a fairly good example of a properly designed double-blind protocol. In this experiment two different tests were performed - one involving a buried water pipe and the other with one target in ten locations. One possible concern regarding the target test is that the boxes may have been placed too close together.
Part I is from Swift, Vol. 1 No. 1, 1997. Part II is from Swift, Vol. 1 No. 2, 1997. Reprints of these are available for $6 each from: