A HF antenna for amateur radio using a Spiderbeam mast for center support,. 

I wanted more elevation of my wire antenna for better performance on HF bands, especially 40 and 80 meters. Wire length is 90 feet, fed with 40 feet of ladder line.
Raising the middle section of my ZS6BKW (a modified G5RV) wire antenna has helped alot. That put the wire between a Rohn mast and a tall tree.
The Spiderbeam is a telescoping 60 foot mast, it assembles quite easily, using supplied stainless steel hose clamps to hold the sections in place. I did not fully extend it, leaving the top section down. A pulley was secured to the upper section to pull the wire antenna up.
Guying is done by two sections on the mast.