This 7-element logperiodic by KLM is using a 3" boom 10m long.
Its usable from 7 to 60Mhz, balun is a homebrew 1:4 on a large ferrit core.
The tower is 9m high and the rotating pipe is 6m but only 4.5m extended above the bearing.
There is an extension to the mast with 2m of aluminum to bring the total height above the log.
The complete tower will be gamma or omega matched on 80m to use it in an array with my 1/4-wave vertical 20m apart.
As the Log is using isolated elements it will not do too much top loading and the aluminum pipe should also bring the high voltage aeria well above it to prevent arcing of the balun or elements.
I will use 16 ground mounted radials 20-40m long.