On Oct 24, 8:49*am, "Szczepan Bialek" wrote:
...
On Oct 23, 2:48 pm, Ian Jackson





wrote:
In message , Cecil Moore
writes

Szczepan Bia³ek wrote:
It is a history: "In the early days of lightning conductors, I
believe that the French
didn't like the nasty pointy things which the British had installed.
Instead, they decorated theirs with fancy balls at the top - with
sometimes disastrous results.

I assume a certain biased reporting of anecdotal evidence.:-)

A ball at the top hat of a Tesla coil allows a greater
amplitude of voltage to build up before arcing than does
a point at the top. Therefo

Points should result in more lightning strikes at lower
voltages.

Balls should result in fewer lightning strikes at lower
voltages.

Did you mean 'higher'?

Can't think of any valid reason why either design
should be able to avoid the really big one.

Surely, when lightning is about, points allow an essentially continuous
discharge at a low current, while balls allow the voltage to build up
and up, until there is a big 'splat'?
--
Ian
In the end, that's about the way I see it, but I consider

any discharge by either to really be fairly irrelevant.
Trying to avoid strikes by discharge is like whizzing in
a whirlwind. *:/
The sharp point streams much easier than the ball,
so the chances of streaming and connected to a down
leader

No down lider. Excess of electrons is in the stormcloud and they jumps if
the difference of voltage exists. At first they jump inside cloud. Next they
jump in the all directions outside cloud. But the all jumps are in form of
oscillations. Lightnings produce LW.


yes, there are downward leaders. these can be tracked either by their
radio noise or by radar. the size and step process has been well
known for many years.

are much greater than with a ball which will

resists streaming at those same potentials.
If you had a spike next to a ball, I would think the spike
would be struck most of the time.


and you think wrong.

We need here the experimental data. Does anybody know?

yes, but not you.


You need a good streamer going to lure a down leader.

But a ball can still stream if the potential cranks up
high enough, and the resulting strike can often be a
a stout one if it can overcome the poor streaming
of the smooth ball.

The only cause for spark jump is the voltage difference. Spikes decrease it.

no they don't. they provide a better place for streamers to start
because the sharp point increases the voltage gradient helping it to
stream sooner.


The oscilations start from very short in all directions and the last steps
are longest.

there are no oscillation in the step process. and there is no
evidence that the steps change length in any report i have seen.