[TowerTalk] Feedpoint Impedance
hwardsil at gmail.com
Tue Jul 29 11:06:07 EDT 2008
>>> Radiation resistance should be fixed..
>> Oh, right...duh.
>> The current equation will do - but the radiator (I may have confused
>> things by referring to it as a "dipole") may be anywhere between one-half
>> and one wavelength long, so the current won't be a simple cosine
>> function. It *will* be zero at the ends :-)
> I think Orfanidis's book has the equation you're looking for.. actually
> several approximations, of varying fidelity..
> I'm pretty sure there's some standard assumptions of the current
> distribution shape (ranging from uniform for very short, to triangular to
> sinusoidal to something else), possibly broken up into segments.
> What sort of accuracy are you looking for?
20% ought to do it. There will be significant variation depending on
proximity of ground, type of ground, and so forth. At this point, I'm just
doing a feasibility study.
73, Ward N0AX
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