Divide 468 by the antenna's operating frequency (in MHz) [468/f (in MHz)] |
Divide 234 by the antenna's operating frequency (in MHz) [234/f (in MHz)] |
A quarter-wavelength vertical antenna for 146 MHz (measured to the nearest inch) is 19 inches.
A quarter-wavelength vertical antenna for 440 MHz (measured to the nearest inch) is 6 inches.
A quarter-wavelength vertical antenna for 28.450 MHz (measured to the nearest foot) is 8 feet.
If an antenna is made shorter, its resonant frequency increases.
You could decrease the resonant frequency of a dipole antenna by lengthening the antenna.
You could increase the resonant frequency of a dipole antenna by shortening the antenna.
One disadvantage to using a multiband antenna is that it can radiate unwanted harmonics.