Shop Notes 2/6 - Pre-testing for upcoming Tesla Longitudinal mode (FTL) communication experiment.

A test I've been meaning to perform for some time is to measure the propagation speed of longitudinal magneto-dielectric waves.   There are only two known forays into this field.  One is Eric Dollard's 'analog computer' experiments, and Nikola Tesla during his Colorado Springs experiments. 

In Tesla's notes he measures the velocity of signals through the earth as PI/2*C, or about 1.53 times the speed of light, which is patently impossible in the present understanding of science.

My intent is to use a pair of Tesla coils and GPS-disciplined oscillators in order to replicate the experiment and to directly measure the speed of propagation through-the-earth in longitudinal mode.

Before the actual experiment can be done, I first need a pair of functioning coils and a good idea of how much power is needed to get a signal to reliably propagate approx 3.2 miles between home and the lab.

The consensus is that VLF signals propagate far better, and attenuation rises substantially into the HF band.   But, VLF requires much larger coils which becomes more costly and burdensome to build.  So I will be testing a variety of coils on-hand to gauge what I can get away with.

The neat part of a Tesla transmitter is that the antenna is just ballast, all of the signal goes through the Earth.  Thus, a very good earth connection is ideal to get any degree of power in/out.

Prelim tests are being done with a straight wire or very short ground (~12 feet)

This candidate is a bit of a pipsqueak coil that runs around 4.2mhz loaded.   But I have a pair that are very closely matched to each-other, which will save much time winding a second coil..

Cosmic induction generator coils are also paired, but the high wood content creates larger losses than the above.   Also a pair, and these get down to ~3.5mhz.

Chief candidate is a 1-1 Tesla that runs right around 2mhz unloaded.   This one resonates very well as there is almost no core material to impede resonance.

Sadly I am running into issues getting short-term communication established; signal is just too weak.  I either have to look at using a much stronger ground, or using a much more powerful impulse generator to drive it (vacuum tube supply, MOSFETs, or possibly a thyratron)

Initial timing:

Scope shots are attempts to use the GPS oscillator to trigger a pulse generator, so I can reliably create and measure propagation delay between them.

Every 1sec, a series of 10-50 pulses are applied that causes the coil to 'ring up', rising in amplitude each cycle.  Hopefully, using a fixed number of pulses will make it easier to read the result at the reception site.   Worst-case I may have to use a HAM radio on either transmit or receive side (or both).  I want to avoid this because complex radios can often have complex+unpredictable hardware that might throw off my readings.

Predicted results:

Light travels 1.017 feet per nanosecond.

Site distance between Tx and Rx approx 17,000 feet

Thus, expected conventional delay is 17,289ns, or 17.3 microseconds.
 

Using Tesla/Dollard PI/2*C velocity, signal travels 1.597 feet per nanosecond,

making the expected delay 10,644ns, or 10.6 microseconds.

Measured drift on GPS-disciplined oscillators is +-60ns for single measurements, and +-20ns for continuous/long-term measurements.
 

Using above GPS drift values, testing should be accurate to within approx 0.7% for a single test.

Thus, if a Tesla longitudinal-mode signal propagates at ~1.53c, the measured deviation will be approx 75 times larger than the error rate of the apparatus.

End of Part 1...

Preliminary tests are OK.  Not perfect but the GPS timing looks like it will be accurate enough to measure, assuming I can reliably pick up a signal at the other end.

A few more pieces of equipment are on order, and I will have to see if I need to drive more ground rods in.  Next update on this project might take another week depending how much progress is made.

Anyway, hope you enjoyed.🤠

Feel free to ask any questions concerning the experiment or if you're curious about the tech in general.   Few people take the time to thoroughly study and actually replicate Tesla/Dollard's works.