G4CQM's Antennas

WS8C9 8 ele 144MHz special build by Roger Banks GW4WND of The DXShop



Welcome, from mid December 2019 this will be the new home of G4CQM Antennas...

Latest update 4th November 2019

CQMDX designs (Self Build/Homebrew) represent a quantum leap in Derek's development of the AOWA (Advanced OWA) style yagi beam using a simple Split Dipole as the Driven Element! There are no bent elements or different diameters to contend with so construction could not be more straightforward... A clear advantage is to deliver 50Ω Direct Feed with maximum efficiency. Modern computer optimised AOWA yagi designs have no need for outdated/primitive matching systems such as hairpins (shunt matching) and the like!

CQMDX yagis situated in a noisy urban/residential environment outperform LFA's and designs with bent elements in most cases, much lower temperature and better G/Ta! Each design has a relatively shallow Q-factor gradient like that of a highly stable DL6WU long yagi! Meanwhile radiation efficiency >98% in all featured designs ensures best overall performance!

A forensic analysis presentation using Arie Voors free and powerful 4nec2 (NEC based antenna modeler and optimizer) along with detailed build instructions will guide the homebrew Ham Radio constructor toward a successful outcome.

CQM8DXWB seen in 4nec2 (NEC based antenna modeler and optimizer)!
CQM8DXWB seen in 4nec2 (NEC based antenna modeler and optimizer)

NEC Amateur or Professional program?

The Numerical Electromagnetics Code (NEC) was developed (January 1981) at the Lawrence Livermore National Laboratory in California (USA), sponsors included the Naval Ocean Systems Centre and Air Force Weapons Laboratory. It was clearly intended in the first instance for professional use by those sponsor government organisations and was not developed as an amateur program!

The current version of NEC/MOM is due to extensive work carried out by Messrs G.J. Burke and A.J. Poggio.

NEC-2 is user-oriented, the computer code intended for analysis of the electromagnetic response of antennas and metal structures. There are several versions of NEC, NEC-2 was released to the public and is now available on most computing platforms. NEC-2 has been used by several software developers in their antenna software as a reference and method of providing calibration.


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