Topband: 160 metre vertical with 'top loading'

k3bu at k3bu at
Sun Apr 24 18:47:13 PDT 2011

> On the eternally recurring argument about current into and out 
> of a loading coil, here is the way my simple mind has always 
> understood it:
> W8JI is correct in that the current into a perfect inductor must 
> equal the current out of it. It's a piece of coiled wire so 
> where else can the current go? Tom's assumption here is a 
> 'perfect' inductor with no distributed capacitance.

He is not correct!
Have you looked at the "piece" of wire - quarter wave antenna, having the max current at the base and ZERO at the tip? And voltage low at the base and high at the tip - corona?
Where did the current go?
It is the STANDING WAVE circuit, with superimposed forward and reflected RF currents creating cosinusoidal distribution ALONG the wire and not the DC circuit.
Why is it hard so understand that if current can vary along the straight wire, it can wary along the coiled wire too?


> K3BU is also correct because he is assuming a practical 
> inductor, with a finite length and distributed capacitance to 
> ground. That's where the missing current is going, through the 
> distributed capacitance to ground and hence lower output current 
> from the top of the inductor into the antenna.
> Both right, so why the disagreement?
> 73
> Tom G3OLB
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK

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