The OWA design is a completely different idea that uses a parasitic element for matching and to achieve a wide bandwidth. Linear loading does not use a parasitic element.
Linear loading is a loading method generally used with horizontal antennas, but can also work with vertical antennas. Essentially, part of the antenna is folded back onto itself. With a horizontal dipole antenna the antenna goes out from the feed point to the end of the antenna and then is folded back towards the feed point, kind of like a folded dipole only the parts folded back towards the feed point are not connected to each other. The area going from the tip back towards the feed point is the linear loading. This method is also used in yagi antennas for both the radiating element and the other elements. If you need to make the antenna shorter still, you can fold said elements again and head back towards the tip of the antenna.
The ARRL Antenna Book, 22'nd edition says that this form of loading is more efficient than either a coil based load or using a cap hat. It is also something that I didn't really understand, so I was playing with it in modeling. I am aware of elements being so close together causing problems, so I used elements that were farther apart. It still works, although the further apart the elements the more skewing said loading creates in a model. The horizontal linear loaded section model was an attempt to limit the skewing of the model as much as possible, although, like with the I-10K/Shockwave model, it did add a horizontal component.
On an additional note, I also found that for every amount of shortening, there seems to be an optimum amount of separation to use for efficiency, and getting the wires either closer or further from that point affects efficiency to some degree.
I can see how on a yagi such small errors will add up, however, I was not using linear loading on a yagi antenna. I have, however, considered paying the $300 to get Nec4... As of yet I haven't seen the need to drop that much money on it... Should I decide to I can simply drop it into a folder in 4Nec2, and change a setting, and I am working with Nec4.
The DB
