CDX-007, I can't help you to accept the idea that more then one radial is active in any one direction. It is a fact take it or leave it. I've experimented with this antenna enough to know that both the shielding effect and radiation effect of the cone benefited from having the 4th radial added to the design. From your point of view as long as one radial was facing the desired direction no gain would be seen adding the 4th. This is simply not true.
Using a field strength meter at various points along the antenna would show nothing even remotely similar to the CST image. The field strength meter does not react to the maximum current point on the antenna. It responds to increases in RF voltage and shows the highest reading where the highest voltage is. Hold one up to your 102 inch whip if you don't believe me. The highest reading will be at the tip which just happens to be where the least radiation current is.
I don't question that the TOA will suffer from being mounted too low to the ground or that close proximity to other antennas would effect the pattern. I will say it shows no significant change in VSWR where many other antennas do. My point here is my roof and mast are tall enough to remove this variable.
Marconi, I'm not sure what you mean by me pausing. I only tested the GM on the ground first to confirm the antenna had a reasonable match, bandwidth, and could handle my TX power before going through the trouble to install it. I did this because I needed coverage of 10 and 11 meters. In all honestly I did not test signals on the ground but the VSWR did not change.
Unless it was raining, snowing, or your roof is metal, the roof itself really cannot effect the antenna. Asphalt shingles and plywood simply do not effect RF at HF frequencies. In the absence of those conditions during your tests, it was the height above ground that made the difference, not height above the roof. Being that it does snow, rain, and some roofs have metal in them are probably the reasons Sirio recommends 6 feet or more clearance.
