Total posts : 45366
Thanks for the “elevated ground plane” analysis. This idea has come up often in the past. I think you have laid the idea to rest (at least for an elevated antenna out in the open and well clear of obstacles).
Also, thanks for your input on the “mast against the side of the house” installation. Obviously, the best elevated antenna would be one that takes full advantage of the ground lead radiation. This implies a freestanding mast out in the open.
Here is another problem to chew on. Which of the following two installations would perform better:
1. A part 15 antenna essentially at ground level (maybe up on a short pipe of say 2 meters max.
2. An elevated part 15 antenna on a grounded pipe 7 meters long, but immediately adjacent to a fairly conductive building with aluminum siding or stucco on wire mesh.
I realize that the effect of the building siding or adjacent electric wires in the building is a total unknown for modeling. You may be able to use the worst-case situation where the building is a perfectly conductive ground surface.
What I am really asking is whether the part 15 antenna elevated to 7 meters with the grounded surface adjacent to the mast will perform better or worse than a ground level antenna out in the open. This is a practical consideration for many part 15 broadcasters. My gut feeling is the elevated antenna is still better because the antenna will radiate its signal above other adjacent building roof lines. But it is also possible that a large portion of the power will be shunted to ground due to the adjacency of the mast to the grounded conductive surface of the building.