I’m working with Eric Dollard personally this week, learning a ton in the process so I figure I’d share bits of what I’m picking up thus-far.
* Eric is extremely focused on having absolute minimum impedance to ground for telluric communication.
* His ground is a buried pair of old fuel tanks with 1 ohm measured impedance, and even that merely ‘good enough’. The wires leading from tank to shop are probably enough to drop performance substantially. The entire coil and apparatus is eventually going to be sitting outside directly atop a set of electrodes attached symmetrically to the tank ground.
* Impedance matching transformer must also be wound to match well to the 1-2 ohm expected impedance (harder than it seems for ferrite apparently). We’ve been using 61 ferrite for it’s low loss characteristics, but the low mutual inductance might be hurting more than it’s helping in this case. We’ll be doing a side-by-side with 43 ferrite to confirm if this is the difference.
* Ground current is preferably measured with an RF amp meter (thermocouple type). Anything else introduces too much impedance, and current sensors can give inaccurate results.
* Extra coil impedance should ideally also match the ground. An ideal Extra coil in this setup would probably be 1/4in copper tubing rather than wire to meet that 1 ohm requirement.
Once we’re done, I intend on batching up everything together and creating a how-to guide + videos so others can more easily break into this field. (especially the other 2-3 on this team actively working on it)