The antennas on that website that have the highest gain figure are of the co-linear design.
The following from his website:
Latest News: 11 meter Collinear part production (50' antenna shown)
I am the only antenna designer and builder out there that I know of, that has ever made (or even attempted) to make a "collinear" antenna!
Its a 50' (thats right 50 foot) 11 meter ground plane antenna, that is actually
"two" highly efficient 5/8 wave (.64 wavelength to be more precise) antennas in one that are actually vertically stacked and phased together to "double" the gain of my 5/8 wave antennas.
Keep in mind, my regular sized 5/8 wave antennas are already more efficient and already offer more performance/gain than other 5/8 wave antennas out in the market today, so doubling that gain is quite an impressive feat!
Often, this omni-directional ground plane has been known to outperform 3 element beams (but unlike the beam it receives and transmits and puts them on "hold" in "all" directions at the same time)!
I may start offering these 50' antennas next summer, after more long-term structural testing is done.
If you look at the picture you can see the phasing stub sticking out about half way up the antenna.
But I don't understand why the website is still active.
I told a friend of mine about the antennas and he sent an email or talked on the phone (don't remember which) with the owner and was told that he quit trying to sell the antennas. ( don't remember the reason given )
The owner works at the Indianapolis Airport and is a technician/engineer for the communications/navigation euqipment at the airport.
A few years ago he talked with the people that were on the air on channel 16am here in Fort Wayne, In.
Where he claims he is at is Anderson, In. ( about 85 miles from Fort Wayne )
Some people up here said "Boy, he must have a huge amplifier."
But they failed to understand the situation.
If they had payed attention they would have realized that not only did he talk to the base stations here in Fort Wayne (even base stations that were not very capable) he also talked to people in Fort Wayne in mobiles.
If I can remember I think he talked to everyone in Fort Wayne that wanted to try to talk to him.
(Impressive to say the least)
After he talked to everyone in Fort Wayne and the channel got quiet you could hear him talking to the whole state of Indiana and then some.
He would answer someone west cental and into Illinois then you would hear him go back to someone in the south end of the state and then he would talk to somone over into Ohio.
I remember that he talked all over the state of Indiana.
At the time I had an A99 with the top of it over 100 feet and I could talk pretty good but he was talking to people that I had not a chance to hear.
He talked to people in the north west part of Indiana and I still could not hear the people he was talking to.
Some might say "Big Amp", but they would be wrong, because you can't talk to them if you can't hear them.
That's about all I know about it that I can remember at this moment.