Marconi, I'd be glad to measure it but it came with no paperwork. It appears to be about 33' total tubing so I'll wager it to be a 7/8.
There seem to be several lengths posted which are possibilities. I recall the one I tried out being 26' 7" but I may be remembering it a foot short, after all it was 23 years ago... 
If anyone happens to read this whom also has the manual for the Salute 7/8 - I'd love to have a copy.
This is the one with the silly alloy hub atop the 5/8" OD upper radiator tube into which is horizontally threaded a single allen about the size of that found in a Wilson 1000 collar, and which is meant to secure the top 6.5' of 5/16 - 3/16 tubing.
I plan to cut the top just below that piece of sh... uh, alloy hublet, lose the 5/16 - 3/16 and redo with 1/2" - 3/8" tubing.
I'm also working on removing the screws intended for securing each section to the one below it, and replacing with a vertical slit about 2.5" long x 1/8" wide (table saw) and a pair of Breeze, ABA or Tridon hose clamps at the top of each tube, like the Penetrator / I-10K construction design.
Screw screws! - I'm 
-king tired of seeing sections which have fallen down inside of the larger one beneath it...
