A skeleton cone has been substituted for the single element radiator of figure 2C. This greatly increases the bandwidth. If of least 10 elements are used for each skeleton cone and the angle of revolution and element length are optimized, a low SWR can be obtained over a frequency range of at least two octaves. To obtain this order of bandwidth, the element length L should be approximately 0.2 wavelength at the lower frequency end of the band, and the angle of revolution optimized for the lowest maximum VSWR within the frequency range to be covered. A greater improvement in the impedance-frequency characteristic can be achieved by adding elements than by increasing the diameter of the elements• With only 3 elements per "cone" and a much small-er angle of revolution a low SWR can be obtained over a frequency range of approximately 1.3 to 1.0 when the element lengths are optimized.
work over several octaves, the gain varying only slightly over a very wide frequency range.
Commercial versions of the Discone antenna for various applications are manufactured by the Federal Telephone and Radio Corporation. A Discone type antenna for amateur work can be fabricated from inexpensive materials with ordinary hand tools.
A Discone antenna suitable for multi-band amateur work in the v-h/u-h-f range is shown schematically in figure 5A. The distance D should be made approximately equal to a free-space quarter wavelength at the lowest oper-
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