Donald Smith Devices too good to be true

[Wistiti]

Ideally you need a frequency meter.

Yes i have some but in the past i have fried meters (digital) when i play with hv/hf... The reading goes like crazy and they just became useless caure they are no longer acurate.

Maybe by having long wire on the low voltage side to get away from the device wile taking mesurement...
I just wonder if you guys have better way to do it cause im not familliar with it.

[tswift]

Tuning frequency of the resonant circuit can be done approximately by measuring the capacitance of the capacitor and the inductance of the coil separately with an LC or LCR meter. This won't take into account factors like the parasitic capacitance of the coil so the computed frequency will generally be high compared to an actual measurement. You can measure the actual resonant frequency at low voltage by using a function generator to drive the cap and coil in parallel (through a resistor of 1K-10K), while watching the voltage across the LC tank circuit combo on an oscilloscope. There will be a very noticeable voltage peak at the parallel resonant frequency, but to do this you have to have a scope and a function generator. Even then, I have found that the actual resonant frequency in-circuit while being driven with the spark gap is not always quite identical but it's quite close.

So if you want the $20 solution, you can get a cheap LC meter from ebay. They work OK and will get you in the ballpark. The better answer involves better test equipment and more money. I have been impressed with this Hantek DSO I have, they are reasonably priced and so far it's been quite resilient to damage even working around HV/HF. For regular multimeters I have now gone analog, frying digital meters gets old.

[Wistiti]

Thank you tswift for your reply.
I already have this lc meter: NEW UNI T Modern Inductance Capacitance Meter UT 603 | eBay

And this cheap scope:Hantek 6022BE PC Based USB Digital Storag Oscilloscope 48MSA S 20MHz 2 Channels | eBay

I will try as you say...

Hope to not fry the scope...

[Wistiti]

Finally I found a 8" pipe!!!
I may start wind the coil soon

[Wistiti]

ZVS flyback driver

Here is the ZVS flyback driver I will use for the hv side.

[soundiceuk]

Here is the ZVS flyback driver I will use for the hv side.

That is fine but the PVM12 is self tuning.

Mwtj still got his to work with something similar to your flyback driver.

Mwtj has apparently built his own PVM12 now.

There should be some new results published this week. I've been waiting very patiently!

[soundiceuk]

One thing I would like to see is the waveform across D5. What are people using at this point? I am not familiar with fast recovery diodes at this voltage level, but would be able to try a string of lower voltage units which are on hand. Certainly the current demands are tiny, given the 10Meg resistor in series.

Was just reading back through the pages since and spotted this.

I must have missed it before.

Seems like you are having similar problems to tswift.

What diodes did you try?

You need a 20kv, 100ma, 100ns diode.

[soundiceuk]

Finally I found a 8" pipe!!!
I may start wind the coil soon

Where did you find it?

[soundiceuk]

My antenna measurements turned out quite similar to tswift. Using the latest circuit, 5.4.7, it is clear that the spark gap requires voltage peaks coming from the antenna in order to fire. This is quite different from the previous version, 5.4.6, which would energize the spark gap through the circuitry itself.

With the voltage across C1 at 10kV, spark gap spaced as minimally as I could (paper thickness) I am only seeing a discharge about once per second. I suspect that in a climate such as Tesla's Colorado Springs: very dry, high altitude, and electrically active, one would see more rapid sparking than this. In my low altitude, humid situation, with the antenna running under many large fir trees, there is not enough static around to make sufficient pulse rates, despite my trials of tuning to different frequencies. I believe my ground situation is adequate, with 2 1.2m copper coated ground rods, one in a small stream bed, the other in a wet area of standing water.

I await other reports and suggestions. I will consider the previous circuit for tests as well. Also, I will look at the antenna's output signal by itself, but with varying amounts of DC voltage on it, after properly decoupling the scope input, of course.

You need to change what you are using for D5.

I can't quite work out what is going on with those diodes and resistors in the picture.

[Wistiti]

Where did you find it?

At the city construction department.

[soundiceuk]

Unfortunaly i am only about a 300 feet above sea level. A little less than i thought

Just went through my emails and messages.

Tswift = 1000 feet above sea level

Wistiti = 883 feet above sea level

Mwtj = 300 feet above sea level

Serendipitor = 295 feet above sea level

[Mwtj]

That is fine but the PVM12 is self tuning.

Mwtj still got his to work with something similar to your flyback driver.

Mwtj has apparently built his own PVM12 now.

There should be some new results published this week. I've been waiting very patiently!

Driver i used is based on 4046/4049 chips. Changed resistors (potentiometer) and capacitors for tuning.

Red led will light up when in resonance. at the moment with this flyback 75khz (max 35kvdc) input 19v AC half-wave rectified to DC. PVM pcb will be made today.

Different types of flybacks.
(1) from color TV 8kVpp
(2) and (3) from b&w TV 15-20kVpp
(4) diode split transformer 25kV DC
(5) flyback with integrated cascade 25kV DC

[Wistiti]

Driver i used is based on 4046/4049 chips. Changed resistors (potentiometer) and capacitors for tuning.

Red led will light up when in resonance. at the moment with this flyback 75khz (max 35kvdc) input 19v AC half-wave rectified to DC. PVM pcb will be made today.

Different types of flybacks.
(1) from color TV 8kVpp
(2) and (3) from b&w TV 15-20kVpp
(4) diode split transformer 25kV DC
(5) flyback with integrated cascade 25kV DC

Thank you Mwjt for this informationon the flyback!

One thing I just do not understand is why is important to have an adjustment on the hv source... It is not more easy to have a fixed hvdc source and play with the gap of the ppv for tuning the frequency??

[Wistiti]

Im curious...
What is the best price/ft or /meter you guys can find for 40kvdc wire? Let say 22awg like in the last pdf.

[Wistiti]

Im curious...
What is the best price/ft or /meter you guys can find for 40kvdc wire? Let say 22awg like in the last pdf.

I think I have found a really great bargin for the hv wire....
Will let you know soon...