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something like this?
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Yes, exactly like that. It will zap the coil/cap combo at the output frequency of the ZVS driver and the spark should be a continuous hiss. This is the configuration shown on many of Don's schematics and Bruce's original diagram.
In the new modified diagram from Bruce, all that the ZVS does is charge up a cap to a high constant voltage. The small current from the antenna charges the C2/L1 cap/coil combo in the configuration more like the standard Tesla coil primary, where the spark gap goes between the HV supply and ground, and the coil and cap are in series. If you did it this way using the ZVS it might spark 100 times a second and the spark will sound like rapid-fire pulses and can be quite loud. The oscillation frequency of the coil and cap combo is the same in either case and is determined by the capacitance and inductance, not the driver frequency.Comment
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None of my nst's would spark to earth like that so this should be fun to experiment with today. (or maybe I never set them up properly)Comment
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Still nothing spectacular for results...
Has anyone here experimented with the "Plasma tube" device? 4 foot tall plasma tube with a sheet of plastic/copper/aluminum as a plate capacitor. looks easy to make and Don said capable of something like 65000 watts.
[VIDEO]https://youtu.be/-NbmheIGG_Y?t=965 [/VIDEO]Comment
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If What Don said was true, where do you envision the energy is coming from to produce such wattage?
It's just not possible.
There is no doubt Don was a clever guy and his suitcase device was impressive.
In private Don revealed he was using a home made tritium battery inside the suitcase device. The circuit you have seen. High frequency lighting changes everything.
Using ultra high frequency changes it even more!
Keep watching this space.
We are not far away from showing the first replication that is not affiliated with Bruce or myself.Comment
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thank you that is a new one. I just burned up a bunch of high voltage capacitors so now I order more and wait...Comment
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Made a little progress last night, I have the secondary side tuned circuit assembled.* The tuning range is only about plus or minus 5% due to the fixed caps, so it will be necessary to tune the primary side, measure the frequency, then adjust the fixed caps to be approximately correct before using C3 for fine tuning.
Note: yes, the tuning cap is pointing the wrong way around. I wasn't paying attention when I marked the holes for drilling, I'll correct it soon.Comment
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Looking great Tswift!
Just wanted to point out for anyone that is thinking of building.
The ideal wire for L1 is HV wire and magnet wire for L2.
It isn't critical, you could use whatever you have on hand as long as there is no insulation breakdown and resonance can be achieved.Comment
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Actually this bring up another design detail, and that is proper insulation and shielding. The voltage between L1 and L2 in this design could easily be tens of kilovolts and that means they have to be kept well separated, or else insulation capable of the full voltage rating must be used. In addition, the C2 primary side tuning cap is at high DC potential. Something like a soda straw or short length of plastic or stiff rubber tubing must be used to insulate the experimenter's hand from the cap itself. The C3 cap is at floating DC potential but still touching it will add the capacitance of the experimenter's body to the secondary side circuit and completely change the tuning, so likewise it needs to be insulated with a length of tubing.
Even with some tubing for insulation there will still be the problem of hand capacitance to a degree, that will affect the tuning slightly. To really see this effect in action, play with a slayer exciter circuit (which is a very simple low-power CW solid-state Tesla coil) and watch the frequency with either an oscilloscope or a frequency counter while moving your hand and body around near the coil. If there is no topload and just the self-capacitance of the coil, it can be pretty sensitive and just the presence of any objects within a foot or two will change the resonant frequency significantly, several percent or more. The L1 side circuit in this arrangement is less sensitive to this because a lot of the capacitance in the tuned circuit is coming from the C2 capacitor and not just from the distributed self-capacitance of the L1 coil. I've tested this with the function generator and scope, moving your hand around near it or touching C2 affects it a little, but not very much. Depending on how sharp the signal from the antenna is and how narrow the tuning bandwidth of the L1/C2 tuned circuit is (depends on the tuned circuit Q), this might or might not be a big problem. Again, using a soda straw or something to get several inches of separation will reduce this effect.
Ultimately it will be necessary to put the whole thing in an enclosure, both for safety and for shielding. I have an old aquarium but I don't think it will be big enough. One of my ideas was to take the aquarium and line it with some copper mesh on the inside, so you could still see through it kind of like looking into a microwave oven. The tuning rods for C2 and C3 would have to be long enough to protrude out the top, you could use something like stiff fiberglass rods and extend them as long as necessary. Then the top could be acrylic (with copper mesh on the inside face), drilled for the rods to go through, and you could put pretty-looking knobs on it and it should not only work well but look good too. I like building with acrylic, it looks good when you take the time and care to be accurate with it. Acrylic is also very good for high voltage circuits as it has both high dielectric strength and low dissipation factor.Comment
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Antenna tuning
I have a long wire strung up through the trees, over hill and dale. It averages about 3m off the ground, but is less and more as the terrain varies.
I tested the resonance of the wire against my ground (two 4' copper rods connected together, hammered into a totally saturated wet zone) using a function generator with a 1k ohm resistor in series, and the scope across the antenna. I found the 1/4 wave dip in impedance to be about 450kHz. I may shorten the wire a bit on the far end to bring it up to 500kHz, just to make it standardized according to the inventor's ideas. Because of large variations due to ground (including ground lead length) and such, there is no way to know where wire will resonate without testing and adjusting.Comment
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Good job! I got about half my wire erected today. I think I will try using your tuning method, I actually hadn't thought of driving the antenna with the function generator but it is after all a resonant circuit. I'm also interested to see the scope waveform of just the antenna picking up whatever is around without being connected to the circuit. I'm guessing it will be broadband noise but with a peak at the antenna resonance, plus discrete spikes at the frequency of any strong AM radio stations around. This digital scope I have has a spectrum analyzer function but it's very poor compared to a real spectrum analyzer. However, since I don't happen to have a real spectrum analyzer it's also all I've got.Comment
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What you will see mainly is 60Hz and its harmonics. So some form of high pass is needed to get rid of that. Most of the noise I see is actually at the half wave frequency, a bit above 900kHz, as that is a voltage peak. To see anything at the 1/4 wave frequency requires additional matching.Comment
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Donald Smith X-Files
In private with whom?Originally posted by soundiceuk View Post
What other good stuff that you have on Don.
Thanks for the audio presentation.I got the impression that Don hid a lot from Bruce and was even antagonistic towards him. Before Don "lost his marbles" (according to you) I believe his best came out with the tesla conference video.
After that the PTB ****ed him up good.Comment
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