Nonetheless, when all wires have the same diameter and other modeling geometry guidelines are met, all modeling programs give equally usable results. A folded dipole of this construction would have a calculated feedpoint impedance of about 533 ohms. It should be noted that the impedance transformation equation does not account for the end wires. The test used models of similar construction to those used with equal diameter folded dipoles. Since the tapered model was not reresonated, its values are lower, but the large equal-segmented model is likely the more accurate.
Tapering throws the values even farther off the mark.
Although somewhat better, NEC-4 values are also highly unreliable. Moreover, reducing segmentation of the NEC-4 models produced nothing reliable. The conclusion is that NEC-4 remains deficient in this regard, and antenna modelers are duly cautioned. The inadequacy of NEC-4 to model this situation adequately casts doubts on a number of possible modeling challenges. For example, modeling gamma and Tee matching sections as physical elements contributing to the radiation pattern as well as to effecting an impedance transformation is now dubious.