[TowerTalk] Rotating Dipole

[Dick]

I am in the process of putting up a full size rotating dipole for 40 meters..
I plan to later shorten it to a loaded 40 foot dipole...the ultimate goal is 
to contruct a 2 element beam on 40...I need a source of loading coil core
forms that are about one inch diameter.  Also trying to decide if loading 
the elements  or center loading the driven element woud be more efficient..
any ideas...Dick W4NTG