I checked the model with 16.4' foot mast and the radiator is 17.3'. I didn't find any problems, so you're right Bob.
The PDF files below:
1. shows the A99 that is 21' feet to the feed point, with a 40" inch mast, no ISO, no Choke, with 40:1 transformer.
2. shows the same as #1 with the 40" mast removed from the model.
3. shows the same as #2 with the transformer removed from the model.
I set each model to Free Space, so I could see the Average Gain error report at the bottom of the Eznec Control Screen. The gain for all 3 models were under-stated a little. So I made a note, adding the error value to the gain for each model in the Far Field pattern report...that shows us the gain and angle reported by the model.
This tells me that my model with the 40" inch mast and with the transformer needs some work, because the error of -0.50 db is out of range for good accuracy.
This is like working on a real world antenna, it can be full of surprises, and is not always easy.
