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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]
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 exclusively allocated to amateur radio worldwide.
Gain or 'absolute gain' is defined as "The ratio of the radiation intensity in a given direction to the radiation intensity that would be produced if the power accepted by the antenna were isotropically radiated". [1] Usually this ratio is expressed in decibels with respect to an isotropic radiator (dBi).
It is also possible to depict the directive gain of the antenna as a function of the direction. Often the gain is given in decibels. The graphs can be drawn using Cartesian (rectangular) coordinates or a polar plot. This last one is useful to measure the beamwidth, which is, by convention, the angle at the −3dB points around the max gain.
The problem is now finding how to break the loop without affecting the bias point and altering the results. Middlebrook [3] and Rosenstark [4] have proposed several methods for experimental evaluation of return ratio (loosely referred to by these authors as simply loop gain), and similar methods have been adapted for use in SPICE by Hurst. [5]
The latter factor is quantified by the antenna gain, which is the ratio of the signal strength radiated by an antenna in its direction of maximum radiation to that radiated by a standard antenna. For example, a 1,000 watt transmitter feeding an antenna with a gain of 4× (equiv. 6 dBi) will have the same signal strength in the direction of its ...
A quad antenna is a self-resonant loop in a square shape; this one also includes a parasitic element.. Loop antennas may be in the shape of a circle, a square, or any other closed geometric shape that allows the total perimeter to be slightly more than one wavelength.
[134] [135] Since a half-wave dipole has a gain of 2.19 dBi and a radiation resistance of 73.1 ohms, a quarter-wave (/) monopole will have a gain of 2.19 + 3 = 5.19 dBi and a radiation resistance of about 36.5 ohms. [1] [22] The antenna is resonant at this length, so it's input impedance is purely resistive.