Kapanadze Cousin - DALLY FREE ENERGY

[verpies]

There is an easy trick that you should try with that nanopulser.
Namely, use an open coaxial cable instead of the C1 capacitor.
I tried only a straight piece of coax but maybe a piece that is coiled over a plastic tube, also works.

The coax's capacitance will do the job of the C1 capacitor and Q1's avalanche will create a falling pulse, that will have the same effect as feeding the coax with a rising pulse.
Cheap, easy and effective.

P.S.
With a coax that is long enough, you should even be able to observe the reflected pulse from the other end of the coax (the open end). Scope probe placed at collector of Q1, just as before.

[itsu]

I could try that.

I did hook up my Dally main coil (shorted) coax to this pulser, and there appeared a negative (reflection) pulse 66.4ns behind the main pulse.

Doing the math (speed of light: 299 792 458 m/s  =  0.299792458 m/ns  x velocity factor of my coax which is 78% (foam)) i end up with 15.52 meter, divided by 2 is 7.26 meters (hmm i thought it was 6,6 meters).

Regards Itsu

[verpies]

Doing the math (speed of light: 299 792 458 m/s  =  0.299792458 m/ns  x velocity factor of my coax which is 78% (foam)) i end up with 15.52 meter, divided by 2 is 7.26 meters (hmm i thought it was 6,6 meters).

This is fun, isn't it?

Apparently the velocity factor in your coax is not 78% of c.
Measure the length of your coax with a ruler and solve for the velocity factor.
You can trust your ruler (centimeters) and your scope (nanoseconds) much more than you can trust the coax manufacturer's specifications.

I'm not clear how long your coax is but if L=6.6m then V_F=66.31% of c. (which would mean that this is not an RG-8X cable)
BTW: the round trip time of 66.4ns for the reflected pulse is very clear.

P.S.
It would be interesting to see if the velocity factor of a straight coax differs from the velocity factor of the same but coiled coax.

[verpies]

I have to warn you that if the resistance connected to the emitter of Q1 is not equal to the intrinsic impedance of the coax then the reflected ns pulse will reflect from Q1 again into the coax, and you will get multiple echos. Each echo will be weaker because of the loss incurred while traveling inside the coax.

[TinselKoala]

Nice work, folks. TDR on a shoestring, I like it very much.