Below is the 36' model done earlier where I added 6" of isolation at the top of the mast. Just for the heck of it, I did another model where I added two 1/4 wave radials, slanted down. Slanted radials happened to result in a better setup than the ones with horizontal radials, but the results with radials attached seem to indicate that the radials primarily add more high angle RF to the pattern and thus reduced the RF for the lower lobe.
Bob you're right, isolating the mast/antenna would seem to mitigate the problem currents, just as the article argues, but other measures might also need to be done to correctly fix the problem if the modification was not at the right height. Neither method alone, isolating or finding a better height (length for the mast and feed line) would seem to solve the problem. I think the problem is due to Kirchoff's rule as noted in the article, this problem appears to be too complex to provide us a one fix solution.
For sure if I selected the right height, I would also have to effectively choke the feed line, or else the undesirable currents would tend to flow on the shield to ground.
IMHO, antenna height might be a more complex factor to consider in any antenna installations than most think about. This might be the unsung factor for why we see different guys provide us totally different results with the same antenna, and where we hear location, location, location. I think that location matters due to Earth conditions, which I consider significant to antenna performance, but if this idea regarding height is true, and in all case, then antenna feed point height must be considered as well. Height may be more than just raising your antenna higher...hoping for more far field range.
Generally, most would think that height is always better, but if my modeling is even close, it tends to support the idea that height is more than just raising the antenna. Different heights also seems to dramatically changes the antenna performance and characteristics, and dramatic changes seem to be albe to occur within small changes.
Over time messing with my antennas I also saw this inexplicable changing going on, but I could not understand why. I surely couldn't explain it.
The models below seem to support the idea for isolating the antenna from the mast, but it has to be understood that the feed lines are not part of the models, so just isolating the mast might not solve the problem. But IMO, if it does then the antenna height might be what is working for you.
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