The scope trace above was made with a fiber optic voltage probe across the tank capacitor,  a .02 uF 45kV Maxwell unit.  The spark gap is my single static vortex gap, electrodes set to .295".  No secondary was installed.  Zero volts is on the center line, and each vertical division represents 10kV.

The gap firing voltage is far from consistent.  While some variation may be explained by the fact that with a static gap, the bang-to-bang interval varies, so the amount of ions present in the gap will also vary. But the thing that I can't understand is the occurance of ~10kV bangs shortly aftera major bang.  Sometimes there appear to be a very large number occurring sequentially, like at 30 and 70 msec.

I don't know if this is something specific to my vortex gap, to single static gaps, or to static gaps in general.  If this really is happening, and I have no reason to think the observation is wrong, it may suggest why the use of a static gap is inherintly inferior to rotary gaps.

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