# Slim Jim Antenna Calculator

Slim Jim Antenna was designed by late Fred Judd. It uses a matching system similar to j-pole antenna. It is the most effective antenna when compared to other ground plane antennas. It has two electric poles charged positive and negative. Use this online slim jim antenna design calculator to find the actual wavelength, overall length, half wave radiator section, quarter wave radiation section, feed point, gap and spacing of Slim Jim antenna by providing the frequency and velocity factor.

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Slim Jim Antenna was designed by late Fred Judd. It uses a matching system similar to j-pole antenna. It is the most effective antenna when compared to other ground plane antennas. It has two electric poles charged positive and negative. Use this online slim jim antenna design calculator to find the actual wavelength, overall length, half wave radiator section, quarter wave radiation section, feed point, gap and spacing of Slim Jim antenna by providing the frequency and velocity factor.

Code to add this calci to your website  #### Formula:  Actual Wavelength = 300 / f Wavelength Considering Velocity Factor = 300 * v / f Overall Length = 22500 * v / f Half Wave Radiator Section = 30000 * (0.5 * v) / f Quarter Wave Matching Section = 30000 * (0.25 * v) / f 50Î© Feed Point = 30000 * (0.025 * v) / f Gap = 300 / f Spacing = 30000 * 0.02175 / f Where, v = Velocity Factor f = Frequency

#### Example

If the frequency and velocity factor is 30 MHz and 10 vf, then
Actual Wavelength = 300 / 30
Actual Wavelength = 10 m

Wavelength Considering Velocity Factor = (300x10) / 30
WCVF = 100 m

Overall Length = 22500 x 10 / 30
OL = 7510 cm

Half Wave Radiator Section = 30000 * (0.5 * 10) / 30
HWRS = 5000 cm

Quarter Wave Matching Section = 30000 * (0.25 * v) / f
QWMS = 2500 cm

50Î© Feed Point = 30000 * (0.025 * 10) / 30
50Î© FP = 250 cm

Gap = 300 / 30
Gap = 10 cm

Spacing = 30000 * 0.02175 / 30
Spacing = 21.75 cm