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Roy Lewallen wrote:
I measured current (of which the definition is well understood except apparently by Cecil), and took a lot of care to do it right. Roy, I am not questioning the accuracy of your measurements - I'm sure they are extremely accurate. What I am questioning are your concepts and conclusions about those measurements. As illustrated in Kraus' antenna book, the end- to-end current phase changes by about 3 degrees for a 1/2WL dipole or a 1/4WL monopole. My question for you is: How can a current that changes phase by 3 degrees in 90 degrees of antenna possibly be used to determine the delay through the antenna wire? - or through a loading coil? Hint: The current in a standing wave antenna is of the form: I(x,t) = C1*cos(bx)*cos(wt) + C2*cos(wt+bx) where C1 C2 i.e. the phase changes primarily with t but primarily not with x. For any time t, the measured phase up and down the antenna changes very little. -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
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