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A question was asked Marconi, how would I attach a mast to this J-Pole.


1. Here is my Free Space version of the model for the Real Earth J-Pole that I posted in the beginning of this thread. This model shows the Average Gain and is the bases for the real Earth model to follow.


Next I set this model to the Real World settings...which turned all the losses on and I added an isolated mast. This was done to insure a good Average Gain and the soundness of the real Earth model. This is the model that I originally posted in this thread.


2. Then I took this real Earth model and connected the mast directly to the antenna (no isolation). Here we see a very bad pattern, match, and other performance results when the mast is not isolated from this J-Pole antenna. IMO, this indicates we have CMC's on the mast and/or the feed line which was not model in this project. Notice in this antenna's image there is more current on the mast than there is on the antenna...and that is no-way-no!


Then I added a modeling remedy for the terrible ill-effects of adding the mast directly to this J-Pole, and this model has no isolation (ISO) and the performance results look normal again and no CMC's are to be noted on the mast.


Conclusions:

However, this is not all that is necessary to regain a good pattern and high performance results. This is because we use a feed line in our real setups. This model only simulates what can be done if a good working CMC choking remedy is installed on the feed line or mast, as in this case...where we then see no CMC's flowing on the direct connected mast. If the setup still manifests CMC's then the mast probably needs to also be isolated.


BTW, I would use an Axe handle, or a nice dowel of Redwood, or some good synthetic material for the isolator.