Thread: Eric Dollard
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Old 03-14-2019, 01:27 PM
Marcus Neuhof Marcus Neuhof is offline
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Join Date: Nov 2012
Posts: 80
Quote:
Originally Posted by aminnovations View Post
Hi,

For anyone interested I have made a set of impedance measurements on the Lahkovsky multiwave oscillator (MWO), covering so far:

1. Z11 for the drive coil both with and without the MWO rings, in the range 0.1Mc/s - 20Mc/s.

2. Z11 for the MWO rings only, in the ranges 0.1Mc/s - 500Mc/s and 500Mc/s - 1.3Gc/s.

I have written-up and presented the measurement technique and apparatus, the measured results, and some analysis of the results, in two pages on my website.

Links to the pages are as follows:

Multiwave Oscillator Impedance Part 1
Multiwave Oscillator Impedance - Part 1 | AMInnovations

Multiwave Oscillator Impedance Part 2
Multiwave Oscillator Impedance - Part 2 | AMInnovations

Best wishes,
Adrian
Hi Adrian,
Thank you for your as usual high quality experiments and write-ups.

A few questions that arose in the reading:
  • You cite a presentation by Eric Dollard on the design of the MWO, ostensibly given at the 2018 ESTC. However Eric Dollard's 2018 talk was on the power grid. Where can we find this presentation on the MWO?
  • Your discussion of the SFA adapter board cites the use of equal copper volumes in order to avoid impedance issues. To date I have only seen the 'equal volumes of copper' principle applied in coil design, a very different context. The RF printed circuit / stripline design principles I am familiar with are very different, focusing on e.g track width, board material dielectric constant, distance to adjacent ground planes, board thickness, etc. What evidence is there that the 'equal volumes of copper' approach is useful in the printed circuit board domain?
  • Are the resonant points of the MWO top load consistent with the LC tank circuit model, where the inductance of the ring interacts with the capacitance between the two spheres? Evidence that this is NOT the case might be seen in the coil measurements, where the phase shifts are aligned closely with the impedance peaks. This alignment is not seen so much in the top load measurements. The question of the MWO top load acting as an LC resonator is significant inasmuch as this hypothesised behaviour was the inspiration for Eric Dollard's PCB "golden ratio" antenna for the MWO.
  • Do you have any plans to perform similar measurements on the above-mentioned PCB "golden ratio" MWO antenna?
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