“…stabilized using an external PLL…”

Markus, that’s a really interesting idea.

I wonder how well the conducted spectrum of an open-air arc could be managed by a few digitally controlled loops and all-analog electronics, controlling some of these: trigger rise/fall/delay, sustain rise/fall/delay, ion shaping solenoids/deflectors. In other words, using digital control loops to allow the arc to be the only hardware power switch, with analog hardware performing temporal and spatial shaping of electron and ion currents (in wire and air), for a “green” arc and spectrum*.

Looking at dusty 1935 and 1952 copies of Miller (cold cathode etc.) and J. Dance ’67 (cold cathode), and thinking that digital control loops could leverage 80-some years of cold cathode plasma science for a fun open-air clean-arc QRP transmitter design, based on your intriguing thought of using a loop to manage things surgically.

Shaping a graphite anode and cathode with shop tools could help with spectrum-friendly electrodynamics.

Bandwidths of tiny high voltage power supplies for electric field shaping are suitable for the above (bandwidth even less of a problem for magnetic-field shaping supplies).

In any case, stabilizing using an external PLL is a cool idea for cold cathodes and would be a fun project.      

73, Jim AA5BW

*especially green from a thermal and EMI standpoint if a loose surrounding mesh returns out-of-band fields to the power supply – even optical return using optical integrating hemispheres with ports for airflow  

From: [email protected] [mailto:[email protected]] On Behalf Of Markus Vester
Sent: Sunday, October 7, 2018 4:29 PM
To: [email protected]
Subject: LF: Poulsen Arc?