The grounding system I decided to put in place consists of three ground rods roughly 20 feet from the base and 20ft from each other. As I only have approximately 5 feet of soil on top of limestone, each rod is installed at a 45 degree angle with the top closest to the tower.
I looked into using the exothermic systems to fuse the ground rod to the lead. And in the end I chose to simply braze a #5 stranded copper line which is then connected to the tower leg.
And as copper and zinc don’t get along, stainless steel hardware is used to separate the two dissimilar metals.
I have installed communications shelters from Tierra del Fuego to Alaska and from French Frigate Shoals to Uganda. I have some rather strong opinions on Grounding that I have developed from that work. Stainless Steel is a rather poor conductor but is necessary in the application you have in the picture. To obtain good conductivity consider using a Stainless steel piping repair clamp, discarding the Neoprene sealing pad, around the tower leg. Select its size to wrap nearly completely around the tower leg. Since pipe repair clamps in that size will have to worm gear stainless clamping straps make sure that the Grounding Electrode Conductor (GEC) is under both clamping straps. Take all copper oxide off of the contact portion of the GEC using Emery cloth or aluminum oxide abrasive paper. Apply copper anti-oxidize paste to the copper GEC. If you can afford to do so buy a roll of copper flashing to serve in place of wire as the GEC. By running the copper strap in the bottom of a 3 foot deep trench; or as deep as you can practically get it below the surface when rock bottom is encountered; you will have a much lower impedance Grounding Electrode System than you would with a wire EGC. The EGC will serve as an electrode in addition to being an EGC. FWIW YMWillV.
For the box to which you will connect your conduit or direct coaxial runs to the shack You may want to consider mounting your protectors through the bottom of the box. Since the coaxial cable is shielded, there is no marked advantage to using a metal box. A plastic box would be much less expensive. Install a piece of copper flashing across the bottom panel of the box and mount your lightning protectors through holes which go through both the box floor and the flashing. Cut a thin slot through the bottom of the box along the back wall. Run a piece of copper flashing to ground the piece in the bottom of the box to the Grounding Electrode System (GES) at that end of the coax runs at either the tower or the shack. Join the flashing GEC to the Copper box liner by using 2 copper plates fastened on either side of the joint and held to each other and the copper flashing by stainless steel hardware. [One such joint kit can be obtained from DX engineering but by purchasing copper sheet at a metal shop and making your own you may be able to save money.] Remember to remove any copper oxide from all of the joined copper surfaces and to coat them completely with copper anti-oxidize paste. Do not use NoAlOx or any other anti-oxidant paste that is not meant for copper.
If you prefer you can cut the slot for the the copper flashing to enter the box through the floor of the box at it’s junction with the side wall. Avoid making the slot so long as to markedly weaken the box. Keep the flashing long enough to go all the way to the driven rod grounding electrode. That avoids the expense in time and materials of making the joint between the 2 pieces of flashing. [Joining the copper flashing strap to the rod can be done with the kit available at DX Engineering but you can also make the joining plates your self using copper sheet. Form the sheet tightly around the rod in a U, clamping the rod and the formed sheet in a flat jawed vise, and bending the wings of the U back flat you can also make those yourself.]
If your local soil allows you to drive the rod straight down then drive it through the bottom of a 3 foot deep trench that you will use to run the Grounding Electrode Conductor to the rod. That will extend the reach of the rod toward the permanent water table by an additional 3 feet. 10 foot rods can be obtained at any electrical supply house and for the same reason they are superior to 8 foot rods. If the soil is particularly loose you may want to use rod couplers to “Stack” rods on top of each other to reach a more effective depth. That is probably worth doing if the first length of rod went in quite easily but the only way to be sure would be to use a Grounding Impedance Tester. These can be rented from a few tool rental companies by you may have to make a lot of phone calls to find one that offers them.
Thanks for the recommendations Tom.