Short vertical 160 meter band antenna

A folded monopole antenna system which is physically much shorter than a quarter-wavelength of the lowest frequency of intended operation, the antenna system comprising an antenna base means including an electrical ground means,

• a vertical electrically conducting mast structure supporting a plurality of vertically extending parallel conductors defining a skirt configuration depending from an upper end of said mast structure in spaced relationship to the mast structure,
• an electrically insulating support means for supporting said vertical mast structure on said base means,
• a capacitive loading top hat means supported by and electrically connected to the upper end of the mast structure, said capacitive loading top hat means being electrically connected to and supporting upper ends of the parallel conductors,
• spreader means tensioning lower ends of said conductors downwardly relative to the upper end of the mast structure and maintaining those lower ends in electrically insulated relationship to a lower end of said structure,
• said spreader means being supported by said insulating support means, inductive impedance transforming means between a portion of said vertical mast structure and said electrical ground means,
• coupling means for coupling radio frequency signals between a transmission feed line and said antenna system,
• said coupling means comprising coaxial cable capacitive coupling means between said transmission feed line and a lower portion of said skirt configuration,
• said impedance transforming means providing in combination with said coupling means and the skirt configuration and capacitive loading means on said structure a short antenna having low ohmic losses and high efficiency.

A folded monopole multiband antenna system which is physically much shorter than a quarter-wavelength of the lowest frequency of intended operation, the antenna system comprising an antenna base means including an electrical ground means,

• an electrically conducting vertical structure supporting a plurality of vertically extending conductors defining a skirt configuration depending from an upper end of said structure in spaced relationship to the structure,
• an electrically insulating support for supporting said vertical structure on said base means,
• a capacitive loading top hat means supported by and electrically connected to the upper end of the structure, said capacitive loading top hat means being electrically connected to and supporting upper ends of the vertically extending conductors which are electrically interconnected by the top hat means,
• spreader means tensioning lower ends of said conductors downwardly relative to the upper end of the structure and maintaining those lower ends in horizontally spaced and electrically insulated relationship to a lower end of said structure and to said ground means,
• said electrically conducting vertical structure and said skirt configuration providing a transmission-line interaction,
• impedance transforming means between said vertical structure and said electrical ground means and including inductive impedance transforming means for optimum impedance matching of the antenna system at said lowest frequency,
• coupling means for coupling radio frequency signals between a transmission feed line and said antenna system,
• said coupling means comprising capacitive coupling means between said transmission feed line and a lower portion of said skirt configuration,
• said impedance transforming means providing at said lowest frequency in combination with said coupling means, the transmission-line interaction between the skirt configuration and the electrically conducting vertical structure, and said capacitive loading top hat means on said structure, a physically short antenna having low ohmic losses and high efficiency.