Mounting a dipole vertically as in larry’s pics will have an omnidirectional receive pattern. I would have run the wire inside the pvc to protect it from the elements and those “fat-assed birds”. The use of larger diameter wire or tubing generally increases the usable bandwidth of an antenna.
Someone mentioned disconnecting outside antennas whenever you’re away. I live in an area of south La. that is second only to central Fl in lightning risk and I work in wireless communications. At one time I was responsible for inspecting grounding systems at our towers. Disconnecting an antenna may prevent the induced surge from a nearby strike, But a direct hit, which is no less likely if disconnected, can be dangerous and can cause a fire or kill someone. If you disconnected it and attached it to ground, that would direct the surge to ground. The problem without significant ground conductor is a direct hit to the antenna will probably destroy it and the small feeder line. If not grounded.
Most commercial installations use the same basic principles when protecting against lightning. First, the goal is directing the surge to earth, not preventing it. Those bristles on a stick and other doo-dads meant to mitigate the static build up during a storm are not effective and not used much professionally. On a tower, we ground the shield of the coax feeders to the tower near the antennas, then the shield is grounded near the base of the tower. The tower itself is grounded to a buried ground system. The coax shield is grounded again just before it enters the radio hut or cabinet. Just inside, surge arrestors are installed AND Grounded on the coax. This protects the center conductor of the coax. From this point back to the rf equipment, no more grounding of the feed line. Commercial AC mains is grounded to the same buries system and has what is called a whole building or whole house surge protector. This is a panel with various types of MOV’s banks of avalanche diodes, or gas discharge modules, or a combination of these. Most of the comms gear runs on DC and as such, it is well protected from AC surges due to the surge protector and DC power plant including large battery bank.
All connections to the outside world like ethernet, telephone, etc are also grounded at the building entrance. All significant metal such as doors, door frames, Eq racks, Etc are also ground. The ground leads never make sharp turns, always gradual turns in a downward direction. A surge, especially high energy, does not want to go up. Try to force that could result in arcing off the ground conductor.
The buried ground system consists of standard 8’ ground rods spaced 16’ apart (2xlength). The rods are cadweldelded or clamped to a solid tinned #2 wire that is also buried. Towers typically have one or two rods and a buried ring around them. That ring is connected to the building ground via one or more solid #2 wires also buried. The only exception are guy wire anchors. They are grounded with their own rods, but can be hundreds of feet away and not usually connected to the main ground system.
The equipment is grounded to a 24” large heavy copper bus bar. This bar will have a solid #2 tinned wire cadwelded to the bottome center edge. That goes directly to the buried ring outside. The bar has several holes for attaching wire terminals. One side, let’s say the left side, is where potential sources of Surge are attached such as the coaxial surge arrestors. The right side is the protected side and this is where the equipment grounds go. The theory here is that a surge hits theleft side of the bar and has to pass by the direct low impedance path to ground made by the large wire cadwelded to the center before it can reach the protected equipment side.
At every point, small things that direct the surge to ground combine to protect the RF gear very effectively. I know this sounds like over the top impractical solution for your FM antenna, but you can utilize many of the same principles. Most importantly:
1. All grounds are at the same potential andbonded to your mains ground. Don’t rely upon water pipes and such to accomplish this.
2. Bolt on clamps are fine outside if cadwelding is not an option. You just have to check it once in a while and retighten
3.Never rely upon solder in the ground path. Tinning wires is good. Solder can easily melt During a large surge.
4. We use solid #2 wires because it is durable. You can use smaller copper #6-8to bond ground rods and other connections.
5. bottom line is to have a single point ground that is at the same potential as the mains ground at your service entrance
6. Try to avoid stranded wire outdoors due to corrosion, never bury stranded insulated wire. Some people use wide copper straps to offer the lowest impedance at surge frequencies due to skin effect conductance- even more expensive.
On my ham station, i had a 25foot push up pole with several antennas on it. I had a single ground rod near the basewhich was next to my station. It had a wire clamped with bolted clamp that ran to my home ground rod, I had a wire attached with a pipe clamp around the base of the pole clamped to it( downward direction) and a piece of aluminum with bulkhead so239’ s for each antenna. This aluminum bar was mounted to the wall close to the earth and served the purpose of grounding the shields on the coax cables before entering the shack. It was close to the ground ( the physical ground, but also near the rod) so any high intensity surges would tend to go directly to ground. I only had two polyphaser surge protectors out of 4 antennas - 5 including a long wire in the trees. I had a small copper busbar setup the same as described earlier and grounded all equipment to it in the method described. The ARRL used to recommend a piece of copper pipe used as a bus bar in the same manner. My system with mixed metals and smaller conductors was not as effective as the commercial installations, but more effective than most. My point is it isn’t all or nothing. You can have effective grounding on a budget.
