Passive twins, was Corona bottle cap and twin coils

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Steve Conner <steve@xxxxxxxxxxxx>

> In fact, just
> connecting the bases of
> the driven and passive resonators together with no
> ground at all
> works fine

I've done it with my DRSSTC and I agree that it works
;) I was getting about 2ft arcs connecting between
twin coils driven this way. But I did have trouble
with the system getting unbalanced and high voltages
appearing on the secondary bases.

I used a ~1/8" spark gap (with ~1/2" balls) between
the secondary base connection and RF ground to stop
the voltage here getting too high, and at high power
the gap would arc over and the control electronics
would go nuts. The solid state variac part would turn
itself up to full voltage which led to some scary
moments :-/ It must have been generating a lot of high
frequency rubbish. I think I should have inserted some
resistors in series with the gap to damp it.

I also tried just driving the passive resonator
through capacitive coupling with its base grounded.
Again I got about the same length of streamers from
each resonator, but they just sailed past each other
without connecting. No matter how I tinkered with the
PLL, they didn't connect, and they didn't seem to
avoid each other much either. That led me to suspect
that the two topload voltages were always +/-90
degrees out of phase and I had two orthogonal sets of
streamers that ignored each other totally.

I think using a primary on each coil in a twin system
probably gives better balance and more predictable
behaviour at high powers.

Steve Conner