18 Spark Gap VI Scope Capture

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "B2 by way of Terry Fritz <teslalist-at-qwest-dot-net>" <bensonbd-at-boo-dot-net>

HI Terry, All:
     An ordinary mercury switch (glass) can hold off several KV.  It has a
lower resistance and gives a cleaner waveform.  This will make it possible
to look for other things such as coupling and ground effects.  The power
supply should be disconnected before the gap fires to prevent offset.
Another way to eliminate noise is to use a massive metal slab ground plane
as the ground side of the spark gap.  The scope can be shielded with a
galvanized steel sheet metal box (cheapest method) with BNCs for the
feedthrus (It is battery operated?).  The scope box is then connected
(soldered) to the massive ground plane with a single strap of copper ribbon.

     Better is to put the whole spark gap inside of a box.  These techniques
are used for precision measurements (ESD, etc.).  It is a lot of work and
gets very expensive.  When your setup is perfected then the initial voltage
spike from the discharge of the spark gap capacitance will become apparent.
You are seeing the spike but the subtler parts of the waveform are buried in
the noise.

Cheers,
Barry