Avanti AV-101 free download

File name Avanti_Astro-plane_AV-101_review_TI5LX.pdf

The Astroplane Avanti antenna was invented by Louis J. And Herbert R. Martino Blaese at the end of the sixties and patented in 1971 under registration number 3587109. At that time CB was very fashionable, the equipment operators employed used 23 channels, and a height limitation was imposed so that the antenna could not exceed 20 feet above the maximum height of the building that existed on the property. This limitation was the Achilles heel of the vertical antennas Avanti sold that were 1/4 and 5/8 wavelength, and usually fed at the base. The reason was simple. The Avanti Astroplane antenna emits from the top, the other antennas cited do it nearer the base. This result was whenthe Avanti Astroplane, and the other verticals were mounted at the maximum permitted height of 20 feet, the Astroplane had more coverage to radiate from a greater height. The Avanti in Figure 1 left shows three sections of 1/4 wavelength. At 27 MHz the wavelength is 11 meters, so that 3/4 wave require 8.27 meters, or 27 feet, and this exceeds the maximum height of 20 feet allowed when muntedon a building. Figure 1. Original concept The solution that Martino found was to cut the physical length of the element about 1/8 wavelength. The result was the antenna would have two lower sections of 1/4 wavelength, and an upper 1/8, as shown in Figure 1 right , reaching a height of 6.82 meters. With the shortening, due to the shape of the antenna and the type of material used, the Astroplane would perfectly meet the standard maximum height of 20 feet above a structure. To shorten the antenna Martino employed a well known system called top loading, see Figures 2 and 3. The upper load electrically lengthened the allowed upper element of 1/8 wavelength to 1/4 wavelength. This means that although this element physically measured 1/8 wavelength, because of the top loading, the upper section had a electrical equivalent of 1/4 wavelength. How much longer? It depends on the dimensions of the top load. In this case the load elements of the crossed Capacitor Hat are constructed of 1/8 wavelength radials, and resulted in the 1/8 element achieving an electrical length of 1/4 wave. See Figure 4. Figure 2. T higher load on the antenna used Titanic Figure 3. Higher load types for antennas Figure 4 shows two antennas Avanti to 2 meters. On the left a simple antenna uncharged upper right has placed a mirror, using this analogy to show how the top tube length is extended. This is about the effect of the cross (top load) Astroplane Avanti antenna for purposes of radio waves form a mirror which extends above. Figure 4. Analogy of elongation of an antenna by higher load. The antenna patented in 1971 is shown in Figure 5, consists of an upper 1/8 wavelength, at the end of which a load is placed on cross-shaped elements 4 made up of 1/16 of length wave. The m