Dipole Antenna Length Adjustment
Dipole Antenna Length Adjustments: Building a dipole antenna is easy. All you need is enough wire, the use of an antenna analyzer and a little math. For a half-wave dipole serving a given frequency band you need to decide what your optimum center frequency( cf ) will be within that band. You want the SWR to be lowest at and near your usage part of the band. Maxim A: An antenna which resonates (lowest SWR) at too low a frequency means that the wire is too long and it needs to be shortened. Maxim B: An antenna which resonates (lowest SWR) at too high a frequency means that the wire is too short and it needs to be lengthened. Definitions : λ = wavelength (ft); f = frequency (MHz); cf = band center frequency (MHz); 234 = ¼ wavelength constant = ½ of wavelength constant (468/2); ft = feet; in = inch. element (leg)= ½ of dipole When using either 468/cf, to calculate the total half wave dipole length, or the ...