Re: Copper Tape Antenna Q&A's


Jim Rodrian
 

Barry,

DC resistance has nothing to do with AC impedance.

Ohms Law, V = I x R, is very simple and accurate if you are connecting a 12V
battery (DC) to a 12V landing light. Fifth grade math works very well to
calculate what happens when the battery is connected to the light bulb.

RF (radio frequency) signals are AC (alternating current) signals. When the
frequency of oscillation is in the range of 122.8 MHz, capacitive and
inductive impedances determine what is a "short" or "open" and how energy,
no matter how small, flows through intended conductors. In principle, V = I
x R still works but the formulas are based on college calculus and traveling
wave theory (more calculus). Sometimes the calculus type equations can be
simplified to algebra type equations, but only if valid assumptions are
made. The algebra type equations are usually what you see in the "how to"
literature.

For conclusions regarding antennas, see John Rippengal's prior posts. He
has the experience and knowledge to know what works and what doesn't work.

Jim Rodrian, BSEE
Defiant - in the finishing process

The Experiment :-
Could someone with a very small piece try an experiment?
Mount it to a BARE piece of aluminum and see what resistance value you
can read between the copper tape and the aluminum? . . . . .

Barry

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