[TowerTalk] Modeling "Bent Dipole" (and Conventional) 4-Squares, with Feed Systems
djm2150 at yahoo.com
Sun Jul 23 22:24:05 EDT 2017
If you are thinking about building a 4-square array, or if you would like to do a more thorough job of analyzing your existing array, some recently-developed AutoEZ models may be of interest. You can model vertical elements (on the left in the linked image below) or "bent dipole" elements supported by a tower or tall tree (below right).
Then you can choose one of several different ways to feed the elements. For example, if fed via a hybrid coupler (ala Comtek) the feed system can be modeled like this.
With the elements and feed system both in the model you can run frequency sweeps to produce charts like this.
For a different type of feed system you can produce simulated scope patterns to aid in measuring and adjusting the physical build.
This web page has all the details along with several model files.
Neither the web page nor the models are for beginners. In order to avoid getting hopelessly lost you should probably be familiar with Chapter 11 of ON4UN's Low-Band DXing 5th edition and/or with Chapter 8 in recent editions of The ARRL Antenna Book.
For those not familiar with AutoEZ this page has an overview.
BTW, this post is not in response to the recent 4-square thread started by K4XS although it certainly is applicable to situations like his. It's just a coincidence that Bill happened to post at about the same time I was wrapping up this collection of examples.
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