Abstract: An antenna system responsive to both the E and H fields in a radiated electromagnetic signal relies upon the placement within the influence of a conductive edge formed by an opening in a closed conductive body of an element having an effective electrical length which approximates a resonant length in free space in the intended range of operating frequencies for the antenna.

Abstract: A conductive body having an opening therein, the edge of opening having a length which is less than a resonant length at AM broadcast band frequencies and greater than a resonant length at FM broadcast band frequencies, is caused to operate as an effective antenna over the FM band or over both the FM and AM bands by electrically shortening the length of the edge of such opening at FM frequencies without physically shortening the perimeter of such opening or electrically shortening the edge of such opening at AM frequencies, a common cable or cables being utilized to couple both AM and FM signals to external circuits, switching at the conductive edge thus being eliminated.

Abstract: An improved radio-frequency transformer, particularly useful in conductive-body antenna systems, is provided in which telescoping of two or more portions of the primary of the transformer results in increased compactness, high effeciency and decreased cost.

Abstract: An improved antenna system for the transmission and/or reception of electromagnetic signals is described which utilizes a region or regions of natural current concentration within the conductive portion or portions of fixed or mobile structures for the extraction or insertion of electromagnetic energy.