This page contains some wonderful images of the two now decommissioned marine NDBs, which were operating in northern Michigan back in the 1980's. FR-291 shows the Frankfort Light beacon "FR" at Frankfort, MI, which operated on 291 kHz with 25 watts, and L-308 is the Ludington Breakwater Light beacon "L" on 308 kHz running 50 watts. Both of these were on the shore of Lake Michigan. There used to be a bunch of marine NDBs in the Great Lakes, but sadly, they're just a memory now. All had been decommissioned by 1996 to make way for DGPS.
Some new additions on the page are shots of the NDB "CXK", which operates on 251 kHz, from Clam Lake, Michigan, these shots show the Beacon as it was about 20 years ago. These show the "CXK" transmitter in its barn-red paint scheme, and also one of the Rohn towers, which support the 2 wire tophat. Scott tells me that "CXK" is still on the air, and he can hear it night and day from his QTH, which is only about 12 miles away. it's great to know that it is still going strong!