Ad
related to: delta loop antennas on youtube
Search results
Results From The WOW.Com Content Network
A loop antenna is a radio antenna consisting of a loop or coil of wire, tubing, or other electrical conductor, that for transmitting is usually fed by a balanced power source or for receiving feeds a balanced load. Within this physical description there are two (possibly three) distinct types:
the upper half of a vertical full-wavelength loop antenna mounted on the ground (not to be confused with the visually similar but electrically different half-square antenna described below, under array antennas, [u] nor to be confused with the halo antenna, described next). The full loop is cut at two opposite points along its perimeter, and ...
W.G. Wade of the National Bureau of Standards uses a large multi-loop antenna to perform RDF in this 1919 photo. This is a fairly small unit for the era. The earliest experiments in RDF were carried out in 1888 when Heinrich Hertz discovered the directionality of an open loop of wire used as an antenna. When the antenna was aligned so it ...
The operator rotated the antenna, looking for points where the signal either reached a maximum or, more commonly, suddenly disappeared or 'nulled'. A common RDF antenna design is the loop antenna, which is simply a loop of wire with a small gap in the circle, typically arranged to rotate around the vertical axis with the gap at the bottom. [3]
Patch antenna gain pattern. A directional antenna or beam antenna is an antenna which radiates or receives greater radio wave power in specific directions. Directional antennas can radiate radio waves in beams, when greater concentration of radiation in a certain direction is desired, or in receiving antennas receive radio waves from one specific direction only.
Ferdinand Braun's 1905 directional antenna, which used the phased array principle, consisting of three monopole antennas in an equilateral triangle. A quarter-wave delay in the feedline of one antenna caused the array to radiate in a beam. The delay could be switched manually into any of the three feeds, rotating the antenna beam by 120°.
On marine ADF receivers, the motorized ferrite-bar antenna atop the unit (or remotely mounted on the masthead) would rotate and lock when reaching the null of the desired station. A centerline on the antenna unit moving atop a compass rose indicated in degrees the bearing of the station. On aviation ADFs, the unit automatically moves a compass ...
In 1938, George Brown et al. patented a loop antenna with rhombic shape and quarterwave sides. [2] In 1951 Clarence C. Moore, W9LZX, a Christian missionary and engineer at HCJB (a shortwave missionary radio station high in the Andean Mountains) developed and patented [3] a two-turn loop antenna which he called a "quad".