Re: Notes on Terry's observations
Dr. Resonance is correct. A resonate TC radiates both dynamic magnetic and
elecrostatic fields. They are exhibited by both current and voltage nodes.
They are 90 electrical degrees apart. It is very important to first
establish the reference to which you are measuring. Next be sure whether
you are measuring either voltage or current. Voltage nodes are 1,3,5
multiples whereas current nodes are 1,2,4,6.
If you are measuring with a cell phone antenna your are no doubt measuring
current nodes from the magnetic radiation of the the coil. Hence, 1,2,4,6
If you measure capacitvely with a probe capable of detecting varying
electrostatic fields you will pick up the voltage nodes. Hence the 1,3,5
About two years ago I did some similar experimental measurements. For
current measurements I used a stiff piece of #12 guage Cu wire curled into a
large C shape with both ends attached to a small noninductive resistor. The
whole thing was in a circle ~ 6" diameter. Around my 4" coil, I moved the
current pickup up and down on a fixed plastic rod. I resonated the coil
with a signal generator and measured across the resistor with an analog
scope. The magnetic field radiates in concentric fields around the coil.
Later I did some single shots with break out using my tube scope for
measurements. I never hit the probe with an arc.
For the electric field I used a small 1/2 brass ball on the end of a plasric
rod with a lead to a small capacitor which was attached to the RF ground. I
measured across the cap with the scope. It's important to approach the coil
radially and stay away from the coil as much as possible with your body.
The ES field radiates radially from the coil. It's much more easily
perturbed than the magnetic field.
These experiments were mainly for measuring the ES fields of TCs. I did not
measure harmonics. Basically, I confirmed I-max at the bottom of the
coil and I-min approaching zero at the top. V-max was at the top and V-min
approached zero at the base. I reported extensively on the ES field
radiated from the terminal with single shot discharges as measured with an
These experiments are very easy to perform. No doubt they will settle the
voltage node debate.
> A 1/2 wave resonators peaks I (current) at resonance while a 1/4 waves
> resonator peaks voltage at resonance. The secondary coil acts like a
> transmission line if the upper terminal is small to medium size.
> If you connect a sensitive current meter in series with your signal
> generator as you take the measurements you will see the 1,3,5 multiples
> peaking while the voltage peaks from your cell phone antenna are peaking
> 1,2,4,6. This is normal and to be expected.
> Dr. Resonance