Several are listed on the United States National Register of Historic Places,[3][4] the distinctive diamond antenna design has been incorporated into logos of various organizations related to radio and a very large (scale) replica of the WSM (AM) Blaw-Knox tower has been built into the Country Music Hall of Fame and Museum.
[1] To prevent the high frequency potential on the mast from short-circuiting to ground, the narrow lower end of the tower rested on a ceramic insulator about three-foot wide, shaped like a ball and socket joint.
[1] The distinguishing feature of the Blaw-Knox tower was its wide diamond (or rhomboidal, rhombohedron) shape, which served to make it rigid, to resist shear stresses.
In some Blaw-Knox mast designs, the upper pyramidal section was made longer than the lower, to keep the attachment point of the guys as low as possible, to minimize their interference.
The realization of the nonideal radiation pattern of the design caused the diamond-shaped tower to fall out of favor in the 1940s in radio stations, replaced by the narrow uniform width lattice mast used today.
Three other Blaw-Knox towers of unknown heights also used to exist but have since been removed for the following stations: WABC in Wayne, N.J.; WCAU in Newtown Square, Pennsylvania; and WHO in Des Moines, Iowa.
[18][19] Blaw-Knox also constructed a 469-foot (143 m) tall tower in 1948[20] for WKQI (then known as WLDM) located on Ten Mile Road in the Detroit suburb of Oak Park, Michigan.