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ANTENTOP- 03- 2003, # 004

Current Distribution in the A.L.C.


Assume that |Iref-in| = |Iref-out| which satisfies Kirchhoff

Ifwd-in + Iref-out = net current on left side of the coil

Ifwd-out + Iref-in = net current on right side of the coil

Ifwd-out lags Ifwd-in by 10 degrees

Iref-out lags Iref-in by 10 degrees (Iref-in leads Iref-out)

Now let's assume that Ifwd-in and Iref-out are in phase.


So current on the left side of the coil equals Ifwd-in at zero degrees plus Iref-out at zero degrees which is a current maximum point.

Ask yourself: Can we have a current maximum point on both sides of the coil? I trust that answer is obvious.


Ifwd-out lags Ifwd-in by 10 degrees. Iref-in leads Iref-out by 10 degrees. So current on the right side of the coil equals Ifwd-out at -10 degrees plus Iref-in at +10 degrees, NOT a current maximum point.

Therefore, in this example, net current on the left side of the coil
cannot possibly be equal to net current on the right side of the coil.

73, Cecil

and summarized by W4JLE:

If we feed an antenna at the current point, the current decreases as the voltage increases along the antenna element from feed point to end..

That being said, a coil replacing a segment of an antenna (in order to physically shorten it) will exhibit the same properties (relating to currents) as the segment it replaced.








Yuri Blanarovich, P.Eng., M. Sc.


op of: OK3KAG, OK3KGH, OK3KAH, 4U1ITU, XJ3ZZ/1, VE3IBM, CJ3DCB, CG1ZZ, VA1A, VC1A, etc.
President TESLA RC: N2EE, NT1E, VA1A, VC1A - member: ARRL, RAC, Aruba IDA, MRC, FRC

Photo above was taken at VE1ZZ QTH while operating in CQ WW and WPX contests, where I managed to take world #1 spots on 80 and 160m.

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