That design looks similar to the old AEA 10-30 loop, which is a derivative of a DDRR (directional discontinuity ring radiator).

The ARRL Antenna Handbooks of the late 70s and early 80s featured several DDRR construction projects, all using so-called "plumber's delight" construction. Namely, copper and aluminum tubing.

If I was the one putting up such a construct, I would build it from 1-2" copper pipe and scale the outside dimensions so it'll tune from 3.5-10MHz. This will give you 80/75, 60, 40 and 30M - the latter band being just about the highest frequency where optimum NVIS propagation can be obtained. Use PVC tees, pipe and flanges to space it about two feet off the roof; underneath the antenna, a ground plane made from chicken wire or similar mesh is laid down. The antenna is tuned with a motor-driven variable capacitor whose size and plate spacing will be dependent on the loop characteristics and the amount of power you wish to run through it.

A homebrew version is going to be a lot cheaper than its commercial equivalent, and will be practically invisible from the street if built as I described.