Re: Counterpoise and MMC demise

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

Original poster: "Finn Hammer by way of Terry Fritz <teslalist-at-qwest-dot-net>" <f-h-at-c.dk>

Stephen.

I am sorry to hear of your loss, but there is no reason to add to the
myths, such as that the breakdown voltage of a static gap suddenly
increases. It doesn`t.
Cosmic rays (  :-)  ), uv photons, heat, all make the gap fire at a
lower voltage than that of the stone cold one. The litle droplets of
molten copper that form on the copper pipe gaps when they get really hot
also makes the gap fire at lower voltages, often so low that the
breakrate rises to a fizzing high .
I would think that dv/dt looks like an almost standstill from the gap
point of view, nomatter what breakrate, but I am not sure.

What breaks caps and transformers is the lust for longer streamers,
which makes the coiler increase the spacing of the gap, and thus the
breakdown voltage of it,  beyond the limits of the cap and transformers
ratings.

It is a problem of inadequate measuring equipment, rather than one of
gap unreliability.

Cheers, Finn Hammer

Tesla list skriver:
 >
 > Original poster: "Stephen Conner by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <steve-at-scopeboy-dot-com>
 >
 > At 18:37 19/06/03 -0600, you wrote:
 >
 > >??  If the gap is set to fire at some voltage it will fire at that
 > >voltage. The cap can't ring up beyond that voltage.
 >
 > That ain't so... There is a lot of uncertainty in the firing voltage of
 > static gaps, it varies depending on dv/dt, electrode temperature, and
 > whether a cosmic ray or U.V. photon happened to hit the electrodes as the
 > voltage was at its peak. The uncertainty is easily enough to let the cap
 > ring up to voltages that will kill your NST power supply, as several people
 > myself included have found out the hard way :(
 >
 > Steve C.