Skip to main content

Antenna calculation

Formulas for Dipole and Vertical Antennas

Half-wave antenna in free space (15006 / F) cm
Practical half-wave antenna (up to 30 MHz) (14274 / F) cm
Half-wave antenna (50 to 144 MHz) (14030 / F) cm
Half-wave antenna (above 144 MHz) (14233 / F) cm
Quarter-wave antenna (7137 / F) cm
Full-wave antenna length (30653 / F) cm

J-Pole Antenna Calculator



 A = cm
B = cm
C = cm
(Feedpoint Z = 50 Ohms)
D = cm

"Cubical Quad" Antenna Calculator
Antenna with a tuning stub (Variant A)
Length of each loop side (7564 / F) cm
Distance between loops A (3599 / F) cm
Antenna with a closed-loop reflector (Variant B)
Driven element side length (7625 / F) cm
Reflector side length (7869 / F) cm
Distance between loops A (3599 / F) cm

Yagi-Uda Antenna Formulas
2-element Yagi (Variant A)
Driven element length (14518 / F) cm
Director length (13725 / F) cm
Distance between elements A (3660 / F) cm
3-element Yagi (Variant B)
Driven element length (14426.5 / F) cm
Reflector length (15280.5 / F) cm
Director length (13572.5 / F) cm
Distance between elements A (7137 / F) cm

Y-Match System for Yagi Antennas

Band, m Match tube length L, cm Distance A, cm Max capacitance of variable capacitor C, pF
2
10
15
20
40		 16.5
80
120
170
300		 2
10
14
16
22		 18
50
80
150
250

Note: The table provides approximate data for a Y-match system. These values are valid only if the antenna's input impedance is between 15 and 30 Ohms and matching is done with a coaxial cable of 50...70 Ohms characteristic impedance.

HF Vertical (Ground Plane) Calculator (1-50 MHz)

Vertical radiator length: cm

Length of each radial: cm

Minimum number of radials is 4. The antenna impedance is approximately 30-45 Ohms, depending on the number of radials, their tilt angle, and height above the ground.

VHF/UHF ¼λ Vertical (Ground Plane) (100-500 MHz)

Vertical radiator length: mm

Length of each radial: mm

Number of radials is 4. Radials are tilted downwards at a 135° angle to achieve a perfect 50 Ohm feedpoint impedance.

HF Dipole Calculator (1 to 50 MHz)


Total wire length: cm

Impedance: 50-80 Ohms Length of one leg: cm
Recommended mast height is not lower than m and not higher than m from the ground/roof. Below the recommended height, the antenna radiates mostly straight up (NVIS); above the recommended height, the radiation pattern splits into narrow lobes.

HF Windom (Off-Center Fed) Calculator (1-50 MHz)


Total wire length: cm

Feedpoint Z: ~500 Ohms Short leg length: cm
The feedline drops at an arbitrary length. The antenna impedance highly depends on the suspension height, spatial layout, and exact feedpoint position. An Antenna Tuner (ATU) is absolutely required!

HF Inverted V Calculator (1-50 MHz)


Feedpoint Impedance: ~50 Ohms

Total wire length: cm Length of one leg: cm
The length and impedance of an Inverted V are slightly less than those of a standard dipole because the legs slope towards the ground. Recommended mast height is not lower than m and not higher than m.

HF Loop (Quad/Delta) Calculator (1-50 MHz)


Impedance: 75-120 Ohms

Total wire length of the loop: cm.

A Delta loop is convenient to hang between multi-story buildings. The sides of the triangle can be of different lengths. Recommended suspension height of the top point is not lower than meters from the ground (or roof).

VHF/UHF Vertical Dipole (100-500 MHz)

Leg (tube) length: mm

Requires 50 Ohm coax. The structure consists of two hollow tubes separated by an insulator. The coaxial cable runs up through the inside of the lower tube to the center. The center conductor connects to the upper tube, and the shield connects to the lower tube.
↑ Top | Home
Labels:

Comments

Post a Comment

Popular posts

Introduction to Electronics

Who Is This Tutorial For? This site is dedicated not only to beginner electronics enthusiasts but also to people who appreciate radio electronics as a fascinating field of science and technology, as well as a wonderful hobby. I hope that through my lessons, many will gain knowledge and find answers to questions that may have arisen while studying other sources of information regarding electronics. Since you have visited this page, you must already be interested in what is offered here. Perhaps this is exactly the tutorial you have been looking for, and I believe you will not be disappointed. For people who are already familiar with the basics of electronics and have practical skills, we plan to include interesting sections such as repairing household electronic equipment, communications (building receivers, transceivers, etc.), and microcontroller programming . The idea of creating a step-by-step tut...
Post a Comment
Read more

What is Radio Electronics?

HOW DID SUCH A SCIENCE AS ELECTRONICS APPEAR? The purpose of this lesson is to give an idea of electronics as a science — a branch that, both in the past and today, fills its niche in almost all areas of the national economy, education, and technology. In this lesson, you will also get an idea of the structure of matter and electrically charged particles. We will also touch upon the structure of the atom, the concept of electricity, and the electrification of bodies. At the end of the lesson, there will be a small practical assignment. As the large encyclopedic dictionary tells us, ELECTRONICS is the science of the interaction of charged particles (electrons, ions) with electromagnetic fields and the methods of creating electronic devices and equipment (vacuum, gas-discharge, semiconductor), used mainly for the transmission, processing, and storage of information. Electronics as a science emerged in the early 20th century; initially, it was mainly vacuum electronics that...
Post a Comment
Read more