Re: Best location for spark gap

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

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <teslalist-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
 >
 > Original poster: "Harold Weiss by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <hweiss-at-new.rr-dot-com>

 > Quenching of the gap will be most important.  As I see it, we want to dump
 > all the energy to the primary without it returning back to the cap.  This is
 > probably the reason I would get a 24" streamer at powerup, which immediatly
 > dropped back to 18" for the rest of the run.

I have observed this too. Immediately after I power up the system
(my transformerless coils, by applying full AC power to the NST at
once, without a variac) I see a big streamer. After this the streamers
are usually shorter.
I think that this is due to a startup transient involving the NST and
the primary capacitor, that produces an abnormally high voltage. The
cold gap, that triggers at a higher voltage, also contributes.

About positioning of the gap/primary capacitor in relation to the NST:
If the gap is across the NST output, there is little RF voltage at the
NST terminals while the gap is conducting, but there is RF voltage
as soon as it quenches.
If the capacitor is across the NST output, the situation is reversed.
There is RF voltage at the NST terminals while the gap is conducting,
but little after it quenches.
The difference for the NST seems then to be not so big.

Antonio Carlos M. de Queiroz