| Antenna Length Calculator |
| Antenna Length Calculator | |||||
|---|---|---|---|---|---|
| Frequency: MHz | Type: | Diameter: | |||
| Velocity of light (ISO 1992 standard) (V) = | |||||
| Frequency (F) = | |||||
| 1/2 Wavelength in free space = ( V(km)/F(kHz)/2 ) = | |||||
| Minimum recommended height (1/4 wavelength) = | |||||
| Antenna Element Data: | |||||
| Antenna element diameter = | |||||
| Ratio of 1/2 wavelength to element diameter = | |||||
| Velocity factor of conductor (approximate)(K) = | |||||
| Antenna Element Lengths: | *ALK (Length = ALK ÷ Frequency in MHz) | ||||
| 1/2 λ Flat Top (e.g. Dipole): | |||||
| 1/4 λ Vertical (height) | |||||
| 1/2 λ End Fed, Single Wire | |||||
| 1 λ End Fed, Single Wire | |||||
| 3/2 λ End Fed, Single Wire | |||||
| 2 λ End Fed, Single Wire | |||||
| *ALK = Antenna Length Constant. Includes calculated K and end-effect factors. | |||||
This calculator is an aid for determining antenna element lengths, based on Frequency, Type (Wire or Tubing), and Diameter (AWG#, inches, mm) of the element.
At the top of the calculator, enter the Frequency (1 to 30 MHz) of interest. You can enter any frequency you like, however, the tables are only valid for 1 to 30 MHz. If you enter data outside this range, the value in the entry area will be adjusted. Then enter the Type and Diameter of your antenna element. When using Tubing, the diameter entered should be the outside diameter of the tubing.
The calculator first computes the antenna length (1/2 Wavelength) and recommended height (1/4 Wavelength) above ground, for an antenna in Free Space. The calculator then determines the Length/Diameter Ratio and the approximate Velocity Factor. The Velocity Factor is then used to calculate the Antenna Length Constant (ALK), which includes calculated K and end-effect factors. When the ALK is divided by the Frequency (MHz), the adjusted length is produced.
The botton two sections of the calculator list the ALK and element lengths for 1/2 λ Dipole, 1/4 λ Vertical, and 1/2 λ, 1 λ, 3/2 λ, and 2 λ Single Wire End Fed lengths. Output data is in US/Imperial and Metric formats.
| Table of Horizontal Antenna Lengths from 1 to 7 Half-Wavelengths |
This section contains three tables that can calculate antenna shortening factors and antenna lengths, including quarter-wave verticals over perfect ground, half-wavelength dipoles in free space, and long wire vertical and horizontal antennas. Just enter your frequency of interest in the space provided. While you can enter any frequency you like, the tables are only valid for 3 to 30 MHz. Output data is in US/Imperial and Metric formats. All dimensions are calibrated to NEC-2 antenna models.
Programmed materials are AWG #18 (1.0 mm) to AWG #10 (2.6 mm) copper wire, and aluminum rod or tubing from 0.125" (3.2 mm) to 2" (50.8 mm) diameter.
| Table of Horizontal Antenna Lengths from 1 to 7 Half-Wavelengths | |||||||
| AWG Wire sizes are copper. Other conductor sizes are aluminum. | |||||||
| Frequency: MHz | Wavelength in Free Space = | ||||||
| ¦———— Wire Size ————¦ | Lengths, in Feet | Meters, for N number of ½-wavelengths | ||||||
| AWG | N=1 | N=2 | N=3 | N=4 | N=5 | N=6 | N=7 |
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| Table of Vertical Antenna Lengths from 1 to 7 Quarter-Wavelengths |
| Table of Vertical Antenna Lengths from 1 to 7 Quarter-Wavelengths | |||||||
| AWG Wire sizes are copper. Other conductor sizes are aluminum. Vertical antennas assumed to be over perfect ground. |
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| Frequency: MHz | Wavelength in Free Space = | ||||||
| ¦———— Wire Size ————¦ | Lengths, in Feet/Meters, for N number of ¼-wavelengths | ||||||
| AWG | N=1 | N=2 | N=3 | N=4 | N=5 | N=6 | N=7 |
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| Calculation of K, the Antenna Shortening Factor |
| Calculation of K, the Antenna Shortening Factor | |||||
| KT is the total shortening factor.
KM is the shortening factor due to element material. KE is the shortening factor due to end effect. Values calibrated to NEC-2 models for 3-30 MHz. AWG sizes are copper. Other sizes are aluminum. |
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| Frequency: MHz | Wavelength in Free Space = | ||||
| ¦———— Wire Size ————¦ | ¼-wave Vertical | ½-wave Dipole | |||
| AWG | KT | KM | KE | Length | Length |
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