The newest Ruslan device (4Kw) is running at a much lower frequency of 15khz,  and not 27.3khz as it was running previously.
 So, it's running now at almost 1/2 of the frequency that it was running before.
   The Kacher frequency is at 1.5Mhz now, down from 1.7Mhz, previously.
   So, there is NO exact magic frequency to tune for,  we need to tune for the combined frequencies that gives the best output, instead.

   I just heard that my scope won't be brought to me until August.  Bummer! 

So, there is NO exact magic frequency to tune for, we need to tune for the combined frequencies that gives the best output, instead.

What about having two resonant circuits. The second one resonates at approx. twice the frequency of the first one. The first one pushes (excites) the second one, hence auto-resonance between two coils occurs. That could also be called »parametric resonance«.

Maybe something like that as a very basic principle:

   The newest Ruslan device (4Kw) is running at a much lower frequency of 15khz,  and not 27.3khz as is was running previously.
 So, it's running now at almost 1/2 of the frequency that it was running before.
   The Kacher frequency is at 1.5Mhz now, down from 1.7Mhz, previously.
   So, there is NO exact magic frequency to tune for,  we need to tune for the combined frequencies that gives the best output, instead.

   I just heard that my scope won't be brought to me until August.  Bummer!

In prieviuos Ruslan divice output coil be 37.5 meters, in 4 kW divice output coil is 40 meters. So for this reason maybe frenquency now is not 1.7, but 1.5 mhz?

    Zeit:
   That open coil on the right is the Kacher's antenna, (top load).  It is meant to be used open, to excite the grenade's inductor coil (resonator coil), which is wound under it.
   Most all the explanations of how to tune and what do, have already been given by Akula and Ruslan.  But, no one has obtained the same results.  Yet.
   The trick, I believe is in tuning each running frequency to it's highest best output level, first. Kacher and grenade coils, and then you have adjust them further to produce the best combined output.  That's where a scope and spectrum analyzer come in, if you have them.

Stepanov apparently does not have them. Just two capacitors and two transformers commercially available running at 50Hz. So why should we need that overcomplicated stuff like boxes full of specialized electronics and self-made coils? To me this looks like smoke and mirrors in order to hide the basic principle of work. Otherwise, how can it be explained that someone (Kapanadze/Stepanov/Moray) can stumble upon that effect without any high-end equipment?

People love to over-complicate things. The nature is simple and always same just we perceive it as very complicated and with that mindset all builds are following forced human rules which are not natural and then all consequences are following..

  quote from Hoppy:
  "Good point. This is where experimenters like Nick, who are prepared to spend a lifetime searching for the 'effect', may possibly strike lucky, even without a scope, frequency generator and spectrum analyser."
                                                                      end quote.

   Or two or more life times if needed. But, luck has nothing to do with it. 
    However, I agree that it should not take nanosecond pulses, just to see the effect.
   
   Vasmus does not use very complicated circuitry, either. 
   Dally discovered the "Effect"  by accident.
  SR193, had an output of only 150 watts, but that's a good start. And, like several others, he has also disappeared.
  It always seams to happen, that once someone has something that works, they are not to be heard from, again.
  I was hoping to hear back from Geofusion, but,  no, he's to busy working on other things, or so he says. 
  Kapanadze, after all his working inventions, is still just a poor old sick man. Ending up similar to what happened to Tesla.

   Andray Induction may possibly be the next guy to just by chance,  "HIT IT"...   Looks like he's getting close.

   I had mentioned that I think that "Andray Induction" is getting close, because he DOES have the shown interaction between his Kacher, and the grenade/yoke coils. Which is key in obtaining any additional input from the ambient/ground set up.
 
  Andray Induction's last video, posted one month ago.  Maybe he's had some more "luck" since then, as well.
  https://www.youtube.com/watch?v=bXwfFV4DIyk
   
  It's that "amplification effect", caused by low voltage/ high amps, and high voltage/ low amps pulses, butting heads, at the right time and right frequencies, that can make a difference from just having another conventional working inverter circuit.
   So, the search goes on...

  EDIT:  Let's not forget the Andriej device. Simple two transistor, no yoke set up. Partially lighting a 600 watt load of bulbs, with a short ground connect to the outside water pipe. Although his bulb brightness is not much, but they're on.  He thinks that a 900 watt load is doable.
  He's another one of those guys that we've never heard from again.  How many more guys are out there, that we don't know about? Lots?
  Andriej's translated video, by Wesley:
   https://www.youtube.com/watch?v=eUxFuW3JYdY