KK4OBI'S Moxon Antenna Modeling

the 4NEC2 Optimizer Function


You built a Moxon antenna but it is not resonant at the design frequency, or the gain seems low, or the front-to-back ratio is disappointing. You wonder what to do to improve things?  


You have plans to build a Moxon antenna. You have combed through everything in the MoxonAntennaProject so how to build it is clearly in mind. You have the MoxGen program so you have the necessary dimensions. However, you have your own ideas for construction.  You wonder what will happen to tuning or performance if?


KK4OBI pondered these problems and came up with an excellent solution using the 4NEC2 optimizer functions.  Dick writes:

    As for hams in general I have been in constant awe of the brilliant and ingenious people in the field.  My thoughts about modelers and optimization is probably from forums where the topic is rarely seen and when seen, commonly at the discovery level.

    Having looked at a number of Moxon dimension sets found on the internet, almost all can model at a workable range under 1.8 SWR and usually under 1.5.  The Moxon configuration is quite tolerant of variation. Those using MoxGen dimensions consistently report values mid-way between broad tuning, gain and front-to-back ratio.  Depending on a hams interests or problems, the optimization function can show the way.

Dick provides a PDF document.

Here is something you will be interested in.

Using the meander principle and optimization of the width and height of the meanders, I got some interesting results for same height and wire size at 28.4 MHz.
Moxon: A=12.6 ft, B=1.87 ft, D=2.33 ft, E= 4.67ft, Gain=9.81 & -18 dBi
Meander: A=6.48 ft, B=1.86 ft, D=2.21 ft, E=5.16 ft, Gain=9.07 & -4.2 dBi

It is about half as wide and about 6 inches more on the sides.
Gain goes down about 1 dBi and Back rejection goes down a lot.

I will let you know how the prototype turns out.  --73, Dick, KK4OBI



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