Ludwig wrote:
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.. . .
This suggests that the efficiency of emission versus d (the diameter of
the antenna) should have maxima at "standing wave patterns", that is when
Pi*d is equal to lambda/k (k=2,3,4,...). This is not confirmed by the
radiation resistance formula below (from Bob Sciamanda). Any comment?
Rrad=19200*(d/lambda)^4 effic=Rrad/(Rohmic+Rrad)
Ludwik Kowalski
P.S.
There was an error in the calculation of the numerical coefficient for
the Rrad formula in my last message but this has nothing to do with the
present question.
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Ludwig,
The derivation of the equation you are using assumes r<<lambda and
so ignores any "resonance effects of standing waves". It should serve your
purpose for comparisons at "low frequencies" (r<<lambda).