Moxon antenna

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Moxon antenna for the 20 m amateur radio band
Moxon antenna for the 2 m amateur radio band (144 MHz)
Scheme of the Moxon antenna; the main direction of radiation points to the left

A Moxon antenna or Moxon rectangle is a simple directional antenna for shortwave and VHF frequencies, which is used in particular in the amateur radio sector . It is named after the British radio amateur Les Moxon ( amateur radio call sign G6XN).

Data

The antenna is a rectangle, one half of which is a powered dipole and the other half is a reflector. It corresponds electrically to a 2-element yagi without directors. The angled elements are only about 70% the length of corresponding dipoles. Due to the construction with 2 elements, it has a medium directivity with a forwards and backwards attenuation of approx. 20 dB. The antenna gain that can be achieved is approx. 9  dBi .

construction

In the drawing, the main antenna axis points to the left. The fed dipole is vertical and is bent to the right. The frame construction consists of two insulators marked in blue and the adjoining reflector. The angled elements are similar in shape to an antenna that has been known for a long time, the VK2ABQ Square. X-shaped spreaders made of non-conductive materials such as e.g. B. fiberglass or bamboo (fishing rods!) Are used, on which the reflector made of one wire and the radiator made of two wires are attached isolated. In this way, light antennas with very low wind loads and low weight can be built. The Moxon antenna is therefore also popular for portable radio operations such as summits on the air or field days .

optimization

AC6LA provides a calculation program based on the algorithms developed by LB Cebik, W4RNL. W4RNL has carried out detailed calculations and comparisons on different antenna shapes.

literature

Web links

Individual evidence

  1. ↑ Moxon Antenna Project ( Memento from November 24, 2018 in the Internet Archive ) (English)
  2. ↑ Moxon Antenna Modeling - The 4NEC2 Optimizer Function ( Memento from February 28, 2017 in the Internet Archive ) (English)
  3. ↑ AC6LA: Calculation of the Moxon antenna. Retrieved June 29, 2019 .
  4. ↑ W4RNL: The Moxon Rectangle: A Review. Retrieved June 29, 2019 .