If the analysis demonstrates that it is not reasonably practicable to install, construct, erect, move, reconstruct or modify the proposed WT antenna upon an existing building or structure within the COD, O-1, O-3, LIW2, LIW5, POD, ROL or SED 3A, SED 5, SED 5A or SED 10 Zones or existing high tension power line tower, then, subject to all other permitted conditional use standards, the proposed WT antenna may be located or collocated upon an existing WT tower within the COD, O-1, O-3, LIW2, LIW5, POD, ROL or SED 3A, SED 5, SED 5A or SED 10 Zones.