Construction: My local ACE hardware store stocks 8-foot lengths of angle aluminum, which is what I used for my horizontal tap rod. Their heaviest-duty stock is more than strong enough to support itself plus the top of my gamma rod. I don't support the weight of the entire rod -- which consists of stepped diameters of plumbing tubing -- that way - I simply "steady" the top portion while making electrical connection to the tower at the tap point. (The nearest Lowe's has even heavier aluminum stock, but if you're using wire instead of heavy tubing, the ACE stock is plenty strong enough.) The bottom of my gamma rod sits on a single piece of 2x8 pressure-treated lumber from the scrap bin. I use a couple of scrap lengths of 1x2 furring strips between one face of the tower and the gamma rod to maintain spacing along the length of the rod. It ain't pretty, but it works...I apologize to no one about my signal on 160!
Bud, W2RU >From W0RI: Aluminum and Galvanized Steel will set up Galvanic action in time. Those metals DO NOT mix well. You will end up with a battery in time. I have been shunt-feeding my 80 ft of Rohn 45 tower with monobanders for 20, 15 and 10 meters at 80, 90 and 100 ft for over 20 years. For the shunt rod, I use common thin wall 1/2" EMT. I put a 90 degree bend in the top piece at about 5ft from the end, I take a short piece of tubing wrapped with 400 grit sand paper and lightly sand the tower. I coat the rod and the tower with Penetrox and clamp the rod on with stainless hose clamps. My tap is at 35ft and the rod is 30 inches from the tower. I couple the EMT together with standard compression couplers. Coat the rod and the coupling also with Penetrox. I used some RTV on the top side of the couplings. At the base I drove a 1 1/2 dia piece of PVC into the ground and I use black tye-wraps to secure the rod to the PVC pipe. Put a cap on the end of the PVC to prevent water from entering. I use an Omega match with two 500pf Vacuum variables in a 18 x 18 x 6 inch Hammon steel water proof box. It is U-Bolted to the tower about 1 ft from the ground. The rod is connected to the bottom of the box with a large ceramic feed through insulator, using 1 inch braid. At three places I use short pieces of 1/2 inch PVC tubing to stabilize the rod. Use black tye-wraps on the tower and the rod. The 2:1 band with is ~40kHZ. This is enough for me as I operate 99% CW. The center freq is 1830 with a VSWR of 1 to 1. Outside of that freq I can use a NYE MBV-V tuner. I have drawings and an explanation which I will email if anyone wants. Just let me know. 73......Price W0RI _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK