Basic formulas for calculating antennas. Scheme, description

Free technical library ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING Free library / Schemes of radio-electronic and electrical devices Basic formulas for calculating antennas. Encyclopedia of radio electronics and electrical engineering Encyclopedia of radio electronics and electrical engineering / HF antennas Comments on the article Here are some formulas most commonly used to calculate antennas. Built-in calculators will help hams make calculations easier for various experiments with antennas. The above formulas are taken from various sources and systematized for different antennas. 1. Basic formulas for dipole and pin
Half-wave antenna length in free space = 15006/F(MHz)	(cm)
Real half-wave antenna length (up to 30 MHz) = 14274/F(MHz)	(cm)
Half-wave Antenna Length (50 to 144 MHz) = 14030/F(MHz)	(cm)
Half-wave antenna length (over 144 MHz) = 14233/F(MHz)	(cm)
Quarter Wave Antenna Length = 7137/F(MHz)	(cm)
Full Wave Antenna Length = 30653/F(MHz)	(cm)
Enter frequency : (MHz)

2. Formulas for the "Double Square" antenna

Basic formulas for calculating antennas

Antenna with tuning cable (option A) Side length of each frame = 7564/F(MHz) (cm) Distance between frames A= 3599/F(MHz) (cm) Antenna with a reflector in the form of a closed loop (option B) Vibrator side length = 7625/F(MHz) (cm) Reflector side length = 7869/F(MHz) (cm) Distance between frames A= 3599/F(MHz) (cm) Enter frequency: (MHz) 3. Formulas for the YAGI antenna

Basic formulas for calculating antennas

2-element YAGI (option A) Emitter length = 14518/F(MHz) (cm) Director length = 13725/F(MHz) (cm) Element spacing A = 3660/F(MHz) (cm) 3-element YAGI with a distance between elements of 0.25l (option B) Emitter length = 14426.5/F(MHz) (cm) Reflector length = 15280.5/F(MHz) (cm) Director length = 13572.5/F(MHz) (cm) Element spacing A = 7137/F(MHz) (cm) Enter frequency: (MHz) 4. Y-shaped YAGI antenna matching scheme

Basic formulas for calculating antennas

Range, m	Circuit tube length L agreement, see	Distance A, cm	Maximum capacitance value variable capacitor C, pf
210152040	16,580120170300	210141622	185080150250

The table shows approximate data for the g-shaped matching scheme. The specified values are only suitable when the input impedance of the antenna is in the range from 15 to 30 ohms and the matching is done with a coaxial cable with a characteristic impedance of 50...70 ohms.

5. Line-of-sight radio range

The radio communication range with line of sight and normal atmospheric refraction depends on the height of the antenna suspension and is determined by the formula below:

Basic formulas for calculating antennas

Enter the height of the first antenna (m) Enter the height of the second antenna (m) Communication distance = (km) Literature

1. Bill Orr. Radio Handbook
2. Bill Orr. All about Cubic Quads.
3. K. Rothammel. Antennas.
4. Dolukhanov M.P. Propagation of radio waves. M.Communication. 1972

Author: Nikolay Bolshakov, RA3TOX; Publication: N. Bolshakov, rf.atnn.ru

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