The LOOPQUAD was initially developed in 1973 with refinements over a number of years. I have not found any theoretical coverage of this form of coupled element that permits further analysis. All the development has been impirical at around 1.3GHz. Many YAGI designs have been scaled and modelled to permit performance comparison also in this same frequency region.


My suggestion is that only the broadband model should be made as there is no gain advantage over the original narrow band version. However construction errors will be less important unless the maximum obtainable bandwith performance is desired. The program has built in corrections for size but not physical variations like conductivity.

The effect of conductivity is measurable but the practical disadvantages of using Copper instead of Stainless Steel for the elements is very easily lost by the lack of rigidity copper plated stainless steel would be good ! Optimising gain by looking down the array and aligning the elements is essential and gives a good result. The most recent test session some years ago was to establish and optimise the frequency coverage. This was done by constructing several pairs and using one as the radiating source and the other as the measuring sample. By duplicating the antenna under test the fall off of performance was doubled ie the 3dB points become 6dB in practice. This permitted small corrections to the design to be made and thus the results obtained from the program became more accurate.

Download Loopquad

Click to download a .zip file containing the executable program.

The downloaded program should work on all versions of Microsoft Windows and the interfaces are simple enough that they are likely to work fine in an emulator on Mac OS or Linux. Sugguested emulators are:

  • WineBottler - A free Windows emulator for Mac OS X
  • Wine - A free Windows emulator for Linux distros

© Michael Walters 2010 Website by WaterPigs Web Design

© Michael Walters 2010 Website by WaterPigs Web Design