A few mo. back I installed a used home built 45 ft tower. And old Ham biult this tower with a 1 ft sq. crankup platform and a sopprt for an antena mast. I've been using it form my 2025 watt motor conversion geny.
I used 1.5" schedul 80 black pipe 8 ft long . There is a support at 4 ft. above that sets a 3 blade set of 7 ft Lakota blades.
A while back we had some 40 mph wind and it bent the black pipe at the 4 ft juncion.
I'm just about done with the upgrade. It sure is nice to just turn a crank and the littel elivater brings everything down to the ground for repairs.
The next mast has a 2" outer pipe and it is stationary. It also has a new pice of 1.5" schl. 80 black pipe in the center. The 2" pipe is 8 ft long. The 1.5" is 10 ft long. There is a large flange bearing at the platform base and another bearing at the top of the 2" pipe.
This alows the 10 ft 1.5" pipe to turn inside the 2" pipe. there will be about 1 ft of 1.5" pipe sticking out of the top of the 2" pipe.
This will be a very strong double mast setup and a yaw bearing at the same time.
I've allready done this with 1 pipe only on the side of a doaner power pole using 2 very large pillow block bearings 6 ft apart. Works very smooth.
JK TAS Jerry