Another good use for those concrete form tubes is making antenna carriers.
Made one for a three element yagi, A3S, and it works fine.
Put a couple of tubes together so it was just over 14 feet long.
Added two garage door "D" handles, put a plug in one permanently and a
removable plug, held in place with Velcro in the other.
Now for Field Day or SkyWarn Recognition Day we can just pick it up, put it
on the trailer, hold it down with a couple of tarp straps and drive off.
Very easy to get the antenna in and out of the tube.
Protects the antenna and makes transport a snap.
All elements are left at their fully assembled length, no break down
required.
With a 10" inch or larger tube the fiberglass mounting tube for the driven
element does not even need to be removed.

K7SAM