The short Windom someone mentioned is made by Radio Works. I have a friend here who ran that shortened antenna for a brief time, and went back to his G5RV. I like the full size 80 meter windom, but, it is sometimes not very happy when installed as an inverted Vee. With that tower already in place, I would look seriously at the single wire Alpha Delta sloper. It is about 70 feet long. One end is connected to the feed line near the top of the tower, and the other end slopes downward to a support that is 8 or 10 feet above the ground. With no large beam atop the tower, you would have to run one or two ground wires down the tower, and connect them to ground rods at the bottom. You could help the tuning of the sloper a bit by placing a capacitance hat on top of the tower, along with whatever antenna you want for vhf and uhf. Bottom line, the more stuff you have on top of the tower, the better either the single wire sloper or the two wire version will work. The 2 wire version will cover 160, 80, and 40. The one I ran for awhile also worked on 30. I think the single wire version is advertised to work through 20 meters. I believe the High Power Antenna company also makes a single wire model. If you want to stay with the G5RV, then do as has already been suggested. That is, put as much mast as possible above the top of the tower, and use several stand off insulators to hold the twin lead away from the metal. . The antenna itself will help to guy it, but you may need to add one more guy point, which can be a good quality outdoor rope or close line type cable. Mike Duke, K5XU American Council of Blind Radio Amateurs