[TowerTalk] Tips for Modelling swaged antenna tubing sections

[john at kk9a.com]

With NEC2 I avoid using short wires. If I had a swedged element I  
would use the length of the unswedge portion of the larger tube and  
for the next wire I would just add the length of the swedge portion of  
this tube to the smaller tube that fits inside it. The 1/8 difference  
in diameter for the small overlapping area should not make a  
difference on HF and I feel that the segments are more equal and that  
the model will be reasonably accurate.  Does NEC4 model short segments  
more accurately?

John KK9A



jimlux wrote:

but does the model actually show much difference? One can get way down
in the weeds with this - put a tapered segment in that's 1 cm long, etc.
But if the wavelength is 20 meters, a 1 cm transition is 0.0005
wavelength.  I'd worry more about numerical instability than model
accuracy at that point.