Thaelin:
  I am already down stepping the HV voltage down to 12+ volt for the feed back path, back to the input side. And I'm seeing an increase of output at the bulbs, when the feed back path is connected up, as compared to when it's not.
  I would like to feed back a higher voltage, but 12+ volts is all I have obtained up to now. The feed back voltage/current is dependent on the input source, so if I raise the input to the device, the feedback circuit will respond with a higher voltage back to the input side. That's as far as I've gotten up to now.

  EDIT:  Here's a pic of what I've got going. The 12v feed back circuit is seen on the left of the image, which is a rewound flyback core, filter cap, and 1/2 wave diode bridge.

  Thaelin:
  I am already down stepping the HV voltage down to 12+ volt for the feed back path, back to the input side. And I'm seeing an increase of output at the bulbs, when the feed back path is connected up, as compared to when it's not.
  I would like to feed back a higher voltage, but 12+ volts is all I have obtained up to now. The feed back voltage/current is dependent on the input source, so if I raise the input to the device, the feedback circuit will respond with a higher voltage back to the input side. That's as far as I've gotten up to now.

  EDIT:  Here's a pic of what I've got going. The 12v feed back circuit is seen on the left of the image, which is a rewound flyback core, filter cap, and 1/2 wave diode bridge.

NickZ, I think you might want to change the radiator (antenna) on the grenade coil, this should be a copper pipe of 4mm in diameter (like a 1/4" copper pipe). Remember the voltage and signal being presented is running on the surface of the wire thus a stranded or solid core will not provide the same effect as a hollow core conductor. I would change both (on the kacher/tesla coil and on the grenade coil) as this might provide a better radiating of signal.

I know some of them use a large gauge stranded wire but the same idea applies here as well. We are looking for similar mass of the radiator.

   As both Akula and Ruslan are using the same insulated house wiring like I'm using for the Kacher's antenna, as well as for the Kacher primary coil,  I'll stick with that for now, but may try it later.  Thanks.

Just to be clear , I am building this unit as well. I have finally gotten more free time so I have started winding my coils and collecting the parts I think I will need, currently my Tesla secondary is wound and resonates at 1.75mhz, I will pull off a turn or 2 to increase the freq to 1.8mhz. The Grenande coil portion will be wound this weekend and will be checked for its resonate peak and I will then tweak the unit to match the stages.

I will also be making the primary and radiators using the copper tubing then doing my tuning tests at that time. I will post some pictures of the various stages of build later when I am done making the coil assembly.

I will share more as time permits and show my testing and output waveforms when appropriate.

https://youtu.be/cMMjlOBg_iY

Few things to help you out:
1) The Tesla coil has to be much longer, preferably 2x of coil length of grenade or 4x. The output voltage should be at least 5kV+
Anything with 20 cm+ away should pick up very strong field. Obviously the scope probe must be much further away otherwise it would burn out your scope. And you cannot have ground loop from driving circuit there so either disconnected UPS from mains or battery power source is required.
2) The tuning cap in series to grenade primary coil is for series resonance and the resonance frequency must be resonant even harmonics of Tesla coil (/2x, was /50 in Ruslan's case). The output voltage on cap there should reach must higher voltage level than you are powering in (most likely 10x or more). Without Tesla coil powered in it should consume lots of amps and this is what series resonance usually does. The output of second Yoke's coil over output of second coil in grenade on the load effectively should function as step up transformer in series resonance + choke without Tesla coil.
3) The effect should be at least same as in https://www.youtube.com/watch?v=qmirRN3O6Ko for a start (just the Tesla coil instead of antenna in that video) and the copper tube coil on top is actually capacitive top load of Tesla coil where the second virtual capacitor plate is grenade coil. The nature of current from the ground is electrostatic where capacitor placed in middle between charge and neutral ground source is getting charged instantly. Also the choke next to Tesla coil you seen in akula/Ruslan's video is for slight adjustment of resonant frequency between Tesla Coil and the top load so it can run on best matching frequency.

If you reach to the point where you start lighting bulbs and the current consumption drops on same time  when Tesla coil is ON then you can play around for getting greater pumping effect from the ground wire. Hopefully this helps...

Cheers!

 
  Ruslan has mentioned that while making the Kacher, and grenade coils exactly as he has shown, no further tuning is required to these coils.  Except for the ferrite rod to help adjust the antenna output and frequency. Although no one has mentioned just how to tune this ferrite rod and its inverse coils.

  I haven't seen any of us here able to light 500 to 1000 watt loads, or higher loads, like the 2300 watt output that Ruslan has obtained, without overheating the fets. 
Starcruiser, maybe you'll be the first.

Thanks for the advice from everyone, i do have a larger yoke i can try. I have a couple questions if i make the tesla secondary x2 (80M) the grenade or x4  (160M) Then the length as it lays on the pvc will be in the 22 cm or 44 cm range much longer than he shows in the video just trying to confirm it is just 1 layer correct? Also the schematic i have been working with produces a single pulse at the tesla primary at each mid point of the lower 27-50khz range frequecy from the yoke circuit. just confirming this is correct the 1.25mhz shown in my video just seems to be my resonance of the topload capacitor and secondary tesla coil of my particular setup i assume.  My FET will burn out if supply current reaches much above 5 Amp for very long. Seems to be only one getting hotter than the other and it always blows first. Its the one that is being driven from pin 4 of driver ic. I could use some details about what caps and resistors are needed near yoke FETs. And i recon i somehow ended up with the weak FETs so i may be upgrading them as well. Can someone post another schematic the one i am following is an FET eater.

hi Bat1Robin2,

I have mentioned previously the fets likes to driven at 18volts or least 15volts.I have already provided the fets to use in my previous comment to you i think 2 weeks back.
If you merely use 12V regulator the fets would be "under driven" hence the current capability of the fets is not optimized.It's the reason why you get heating on the fets.

I would recommend using 400volts or 600volts rated fets because at 100volts the Bemf itself would heat up the fets regardless even if the fets are properly driven.

Simple test without connecting anything from output of yoke.The power consumed would be around 5watt at 30volts input in my case.

I have not destroyed  single fet in 2 months.Maybe because i  was using a self-resettable circuit breaker 12volts 5Amps(300cycles lifespan but i have approached 50 trips i think) rated even on 30volts supply.

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Today i am testing out a basic EMP generator which is derived from tesla coil but the only difference there is spacing between each turns.
I would be using 500volts...1000volts from bank of capacitors to pulse the generator.

Primary objective is merely to get current flow to earth.
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In another experiment my nanosecond generator is maxed out at 48volts (boosted from 12volts) with the 5 ccw,cw winding on ferrite rod i achieved 2.1kv.

Placing electronics items such as digital temperature reader near ferrite rod would cause the display to produce err1.

Current movement to Earth 2.57Amps up from previous 1.57Amps.



I recall there was mention by Akula somewhere that around 8KV or 30kv pulse is needed.

ok thanks mag.. i was previously using 12 volt regulation with a 5 amp fuse. I was trying to work my way up in power did not realize that issue. i seemed to do good until i started using the new power supply with variable voltage thats when i started blowing FETs.  I appreciate the insight, makes sense now.  How do you keep the tesla from radiating all over everything, even cutting out my radio stations, interfering with every circuit i have even killed my DSL i think and shut off my radio one day??

hi Bat1Robin2,

The typical tesla coil design would radiate unwanted EM wave which is considered a lost into air.

In Akula old video revealed there is sparks from ferrite rod which means if typical tesla coil even if powered by higher dc voltage say 150volts we will not get to see sparks produce at the ferrite rod.

Unless we are driving the specially made tesla coil which is driven by nanosecond pulse which is able to cut through the dielectric layer even air as an example.



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This is my 1st experiment into EMP generator using nanosecond pulse which produced nearly 5KV Vpp merely using 0.77Amps at 12.64volts(9.7watts).

My setup
1)Signal 24khz 60ns fed to IXDD614 (35volts maximum voltage compared to TC4452 18volts max) mosfet driver which is powered by 20volts boosted supply(XL6009 got 3 x step up cheaply from ebay) in order to drive the Cree SIC Mosfet gates properly.84ns achieved with Cree C2M0080120 without negative -5volts supply as recommended by manufacturer.

2)I used Wima capacitor 0.47uf 2000volts connected in parallel with electrolytic capacitor bank which i found out improved the output to nearly 5kv up from 3kv.

3)Tesla coil is winded with even spacing approx 3mm apart provided total 41 turns using 22awg.This is to lower any capacitive built up between windings.


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 Next stage of experiment to change the CREE to APT10035 which as per datasheet is able to handle "3J" of avalanche pulse.This is implemented into my PCB board nanosecond generator which gives 2KV at 48volts.

Primary winding to be altered from 3 to 2 or 1 in order to lower unwanted harmonics or ringing in waveform and try to improve on the output to 7kv if possible.

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Latest update for today-

I found out the Russian PIO capacitors 20uf 400volts which was previously purchased from ebay which was sold as matching pairs is able to perform little better than my 10uf 250volts-WIMA MKP10 capacitor and it's cheaper too.

I am sticking with CREE SIC mosfet since APT10035 don't perform as well as the silicon carbide mosfet.

I have attached my clamp meter reading under A/C mode which i find it strange that the current reading nearer to the pipe away from the device yield little higher reading at 4.66Amps  at times peaked at 5Amps.

The bottom of special tesla coil is connected to the mosfet drain which is also connected to the upper primary coi for maximum output.The lower primary coil is connected to +288volts.
Earth is connected to battery negative terminal.

This current movement to Earth was the key ingredient which all past and present replicators had failed to look into.



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Last planning for the day to rewind my kapanadze coil which few months ago i started with 60 turns.The resonance frequency to light a 5watt 220volts bulb without any pwm generator was at 1.58Mhz.

I would need to increase this resonance to 1.7...1.8Mhz.