I thought that when combining 2 antennas the spacing between the antennas as well as the lengths of the attached feed lines (phasing harness) was frequency/wavelength dependent and relatively narrow. I don't understand how this can be done over such a wide frequency range like the whole UHF air band. Seems the combination would be optimum at one frequency but cancel out at a multiple, i.e when spacing goes from say 1/4 to 1/2 wavelength. 2 antennas combined over a 225-400 Mhz range would have that issue I think unless there's more to this antenna than meets the eye. I asked the seller but they weren't much help. Let me know if you get 'er in the air!