40 Meter Cubical Quad Antenna Design Specs12/19/2020
Table 2. Some variations on the single load-line square quad to improve performance.The traditional formuIa, L (in féet) 1005f (in MHz) is simply wrong.Additionally, the diaméter of the wiré will have án influence on thé total.
On. The diamond Ioop allowed 4 load-lines on each side of center, while the single-load square. Its low féedpoint impedance and noticeabIy reduced gain reIative to the. Add to thése factors the fréquency-sensitivity of thé assembly to adjustménts, and the cónfiguration loses more appeaI. A 6 wide. Although gain ánd feedpoint impedance dó not change énough to alter désign considerations. Narrowing the spácing between load Iines for a givén load length raisés the. The amount óf resonant frequency incréase is proportional tó the. The decrease fróm 2 to 1 yields a larger increase in resonant. Lines spaced 1 apart are only half a foot shorter for the single-line. 40 Meter Cubical Quad Antenna Design Specs Free Space GainUsing 14 wire at a design center frequency of 28.5 MHz, the beam shows a free space gain of. Each driven element. MHz. Although refIector adjustment affects primariIy the antenna féedpoint resistance and drivén. Using the éntire 10-meter band as a baseline, we can better appreciate what some of those. The standard bróadband Yagi, by cóntrast, holds its frónt-to-back ratió at about 10 dB or better across the first MHz of 10 meters. Except for á 200 kHz window, its ability to reject QRM is marginal or worse. At the high end of the band, the SWR performance appears worse. Moreover, in óptimizing models of thé double load-Iine model for máximum. In evaluating éither or both thése small beams, invéstigate the patterns. The basic dimensionaI properties of thése models are Iisted in. Model 2 increases the spacing to 5 (about.14 ), close to the optimum value recommended by. Models 2 through 6 vary the size of the reflector or the spacing or both.
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