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A HB9XBG Full Size Vertical Antenna for the 40m-band on Simplon Pass with view to Mount Fletschhorn. The 40-meter or 7-MHz band is an amateur radio frequency band, spanning 7.000-7.300 MHz in ITU Region 2, and 7.000-7.200 MHz in Regions 1 & 3. It is allocated to radio amateurs worldwide on a primary basis; however, only 7.000-7.200 MHz is ...
Bonnie Crystal was granted the US patent 7,151,497 Coaxial Antenna System on December 19, 2006, after filing in 2003 for new types of coaxial antennas with reduced size providing efficient broadband, wideband and controlled bandwidths, using radiation by the outside of the coaxial elements.
where is the angle between the antenna axis and the vector to the observation point, is the peak current at the feed-point, = / is the permittivity of free-space, = / is the speed of light in vacuum, and is the distance to the antenna in meters. When the antenna is viewed broadside (= /) the electric field is maximum and given by
The antenna's feed point is at the center of the disc. It is usually fed with 50-ohm coaxial cable, with the center conductor connected to the disc, and the outer conductor to the cone. The cone: The length of the cone should be a quarter wavelength of the antenna's lowest operating frequency. [2] The cone angle is generally from 25 to 40 degrees.
In antenna terms, each of the conductors making up the antenna is known as an element. [9] To calculate the net result, NEC breaks the antenna's elements into a number of sampled points, called segments. It uses simple calculations based on the diameter of the conductor and the wavelength of the signal to determine the induced voltage and ...
The far-field range was the original antenna measurement technique, and the simplest; it consists of placing the antenna under test (AUT) a long distance away from the instrumentation antenna. Generally, the far-field distance or Fraunhofer distance , D F r n h , {\displaystyle \ D_{\mathsf {Frnh}}\ ,} is considered to be
Moxon antenna for the 20-meter band.The antenna is the faint rectangle of wires held in tension by the bent X-shaped support frame. Moxon antenna for the 2-meter band. The Moxon antenna or Moxon rectangle is a simple and mechanically rugged two-element parasitic array, single-frequency antenna. [1]
A two-element quad antenna used by an amateur radio station A 4-element amateur radio quad antenna. The two men working on it show the scale. The wire loops are almost invisible, suspended on the ends of the crossed supports. A quad antenna is a type of directional wire radio antenna used on the HF and VHF bands.