Dual frequency vertical antenna
First Claim
1. A dual frequency vertical antenna for radiating a first and a second airwave signal in response to a first and a second conducted signal, respectively, said first airwave signal having a first frequency and said second airwave signal having a second frequency lower than said first frequency, comprising:
- an electrically conductive base member;
a mast projecting upwardly from the base member to a masthead for forming a dipole for radiating said second airwave signal, the mast including an electrically conductive rod dielectrically coupled to the mast;
radiating means coupled said masthead for radiating said first airwave signal; and
feeding means for feeding said first and said second conducted signal between the base member and said rod including a tuning sleeve electrically connected to the base member, coaxially disposed about the mast, and projecting upwardly from the base member for an electrical length of approximately 1/4 wavelength at said first frequency;
a lower mast extension extending from the mast and projecting downwardly from the base member to a foot for an electrical length of approximately 1/4 wavelength at said first frequency;
a lower rod extension coaxially disposed within the lower mast extension and electrically connected to the lower mast extension at said foot; and
a coaxial cable to feed said first conducted signal and said second conducted signal, having an outer conductor electrically connected to the base member adjacent to the mast and having an inner conductor electrically connected to said rod adjacent to the base member.
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Accused Products
Abstract
A dual frequency vertical antenna for radiating a first and a second airwave signal in response to a first and a second conducted signal, the first airwave signal having a first frequency and the second airwave signal having a second frequency lower than one-half the first frequency. The antenna includes a horizontal base member and a vertical mast, including a coaxially disposed rod, projecting upward from the base member to a masthead. For feeding the conducted signals, a lower mast extension projecting downward from the base member and a tuning sleeve projecting either upward or downward from the base member are tuned to 1/4 wavelength at the first frequency and a single coaxial cable is connected between the base member and a feedpoint on the rod. The first airwave signal radiates from a dipole formed of an 1/4 wavelength upper rod extension extending upward from the masthead and a concentric 1/4 wavelength upper sleeve external to the mast projecting downward from the masthead. The mast is 1/4 wavelength at the second frequency for radiating the second airwave signal from a dipole formed of the mast and the base member.
95 Citations
2 Claims
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1. A dual frequency vertical antenna for radiating a first and a second airwave signal in response to a first and a second conducted signal, respectively, said first airwave signal having a first frequency and said second airwave signal having a second frequency lower than said first frequency, comprising:
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an electrically conductive base member; a mast projecting upwardly from the base member to a masthead for forming a dipole for radiating said second airwave signal, the mast including an electrically conductive rod dielectrically coupled to the mast; radiating means coupled said masthead for radiating said first airwave signal; and feeding means for feeding said first and said second conducted signal between the base member and said rod including a tuning sleeve electrically connected to the base member, coaxially disposed about the mast, and projecting upwardly from the base member for an electrical length of approximately 1/4 wavelength at said first frequency;
a lower mast extension extending from the mast and projecting downwardly from the base member to a foot for an electrical length of approximately 1/4 wavelength at said first frequency;
a lower rod extension coaxially disposed within the lower mast extension and electrically connected to the lower mast extension at said foot; and
a coaxial cable to feed said first conducted signal and said second conducted signal, having an outer conductor electrically connected to the base member adjacent to the mast and having an inner conductor electrically connected to said rod adjacent to the base member.
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2. A dual frequency vertical antenna for radiating a first and a second airwave signal in response to a first and a second conducted signal, respectively, said first airwave signal having a first frequency and said second airwave signal having a second frequency lower than said first frequency, comprising:
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an electrically conductive base member; a mast projecting upwardly from the base member to a masthead for forming a dipole for radiating said second airwave signal, the mast including an electrically conductive rod dielectrically coupled to the mast; radiating means coupled to said masthead for radiating said first airwave signal; and feeding means for feeding said first and said second conducted signal between the base member and said rod including a tuning sleeve electrically connected to the base member, coaxially disposed about the mast, and projecting downwardly from the base member for an electrical length of approximately 1/4 wavelength at said first frequency;
a lower mast extension extending from the mast and projecting downwardly from the base member to a foot for an electrical length of approximately 1/4 wavelength at said first frequency;
a lower rod extension coaxially disposed within the lower mast extension and electrically connected to the lower mast extension at said foot; and
a coaxial cable to feed said first and said second conducted signal, having an outer conductor electrically connected to the base member adjacent to the mast and having an inner conductor electrically connected to said rod adjacent to the base member.
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Specification