Shunt feeding the tower for 80 and 160 meters

Modeling a shunt fed tower in MMANA

I realize that there are some real limitations in attempting to model a shunt fed tower for 160 and 80 meters. My configuration does not make the task any easier when it comes to modeling the real world: a self supporting tower with tapered faces, a variable & isolated antenna on top (4 element SteppIR) below a 2 element 40 meter shorty-forty. Nonetheless, I've attempted to put together a quick and dirty model in MMANA to investigate.

As you can see, this antenna is narrow-banded. Modeling took some tweaking to get a system that would work - but this looks to be a real possibility.

Modeled Performance and SWR Plots: 160 meters