Can you re-tune a 'tri-bander' for use on 11 meters? Sure. But it will mean one of two things. You will loose 10 meters. Or, you will not be using a resonant antenna. Neither is a world shattering catastrophe, but that's what will happen. A tuner, at least one on the bottom end of that feed line, doesn't make anything resonant. They certainly do make things more compatible to the transmitter though, which is the whole point of using one.
Gain because of element spacing etc? No idea if, or how much you might gain or loose, it would probably be very comparable though.
Antenna usable bandwidth. Oh boy is that an easy game to play! That's because of how that usable bandwidth is typically measured, by SWR. It really isn't that difficult to 'fool' an SWR meter. That SWR isn't very indicative of how well an antenna is working, or it's efficiency. There are just too many ways of getting an SWR with the 'right' amounts of reactances in it to make a transmitter 'happy'. Unfortunately, depending on exactly 'where' those reactances are and their purpose for being there, reactances do not 'radiate'/produce any signal. Resonance is defined as the absence of reactances leaving only 'resistance', which does radiate a good signal.
So, can it be done? Yes. Is it going to be the bestest thingy in the world? Depends on how you look at it.
- 'Doc
