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Often random wire antennas are also (inaccurately) referred to as long-wire antennas.There is no accepted minimum size, but actual long-wire antennas must be greater than at least a quarter-wavelength ( 1 / 4 λ) or perhaps greater than a half ( 1 / 2 λ) at the frequency the long wire antenna is used for, and even a half-wave may only be considered "long-ish" rather than "truly ...
Assuming the building is about 20 feet tall, the length of wire seems to be on the order of 100 feet long – too short to be an HF Beverage antenna. Random wire antenna Moxon (1993) describes the random-wire antenna as an "odd bit of wire". [14] [page needed] It is the typical informal antenna erected for receiving shortwave and AM radio.
A short antenna pole next to a house Multiple Yagi TV aerials. Antennas are commonly placed on rooftops and sometimes in attics. Placing an antenna indoors significantly attenuates the level of the available signal. [19] [20] Directional antennas must be pointed at the transmitter they are receiving; in most cases great accuracy is not needed ...
Assume a conductor's cross-section dimensions are small compared to the wavelength, current only flows axially along the conductor, the current distribution slowly varies along the conductor's length, and current is approximately uniformly distributed along its circumference (owing to the skin effect). Furthermore, only the current in a ...
The electrical length of an antenna, like a transmission line, is its length in wavelengths of the current on the antenna at the operating frequency. [ 1 ] [ 12 ] [ 13 ] [ 4 ] : p.91–104 An antenna's resonant frequency , radiation pattern , and driving point impedance depend not on its physical length but on its electrical length. [ 14 ]
The length is not critical, typically from one to two wavelengths end-to-end, but for any given length and frequency, there is an optimum acute angle at which the sections should meet. A horizontal rhombic antenna radiates horizontally polarized radio waves at a low elevation angle off the acute end of the antenna opposite the feedline.