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Bud--

wrote:
In alt.tv.tech.hdtv bud-- wrote:
| wrote:
| In alt.tv.tech.hdtv bud-- wrote:
| | wrote:
| | In alt.tv.tech.hdtv bud-- wrote:

| | For example, consider the high frequency issue. High frequency energy is
| | less common than low frequency energy. Partly this is because the chance
| | of a closer lightning strike is less than a more distant one. A strike
| | within 100 meters is only 1/8 as like as a strike outside of 100 meters
| | but within 300 meters. Some people then feel that they can dismiss high
| | frequency energy issues entirely.
| |
| | Francois Martzloff was the surge guru at the NIST and has many published
| | papers on surges and suppression. In one of them he wrote:
| | "From this first test, we can draw the conclusion (predictable, but too
| | often not recognized in qualitative discussions of reflections in wiring
| | systems) that it is not appropriate to apply classical transmission line
| | concepts to wiring systems if the front of the wave is not shorter than
| | the travel time of the impulse. For a 1.2/50 us impulse, this means that
| | the line must be at least 200 m long before one can think in terms of
| | classical transmission line behavior."
| | Residential branch circuits aren't 200m.
| |
| | Your response: "Then he flubbed the experiment." In another case you
| | have said Martzloff had a hidden agenda.
|
| I addressed this one elsewhere. You seem to have misunderstood him.
| He did not say that wiring systems do not exhibit transmission line
| characteristics.
|
| If you had actually read the quote:
| "*it is not appropriate to apply classical transmission line concepts to
| wiring systems*"
| and "*this means that the line must be at least 200 m long before one
| can think in terms of classical transmission line behavior*."
|
| Repeating: "Residential branch circuits aren't 200m."

You are now taking what Martzloff said out of context. He _qualified_
what he said in terms of a statement conditional. Following the part
you just now quoted is "... if the front of the wave is not shorter than
the travel time of the impulse." Then he added "For a 1.2/50 us impulse,
this means that the line must be at least 200 m long before one can think
in terms of classical transmission line behavior."

Hint: what "if" means is that if the conditional is not met, then the
statement does not apply.

Martzloff's statement is actually correct. Your quoting of it is wrong.
I suspect your understanding of it is weak or maybe even wrong. I believe
you are misapplying it. Then when _my_ statement contradicts _your_
incorrect understanding, you somehow think *I* am contradicting him.

His statement is qualified for a specific slow impulse rise time that
corresponds to a lower frequency. He has NOT said (in what you quoted
in earlier posts here) that no surge can ever have a faster rise time.
He has NOT said that you cannot think in terms of transmission line
behaviour for faster rise times, even on shorter wiring/circuits.

Previously you said Martzloff "flubbed the experiment".

Now you agree with Martzloff that branch circuit must be 200m for
transmission line behavior with 1.2 microsecond rise time.

You say that doesn't apply because surges are faster. Martzloff uses 1.2
us because that is a standard rise time for surges produced by lightning
as defined in IEEE standards.

w_' professional engineer source says 8 micoseconds with most of the
spectrum under 100kHz.

You still have *no sources that support your belief* that risetimes are
far faster.

| | You claim lightning induced surges have rise times about a thousand
| | times faster than accepted IEEE standards - which are experimentally
| | derived.
|
| So you are narrowing this statement to only induced surges?
|
| I intended "induced" meaning produced by including the most damaging -
| strikes to utility lines.

The most damaging strikes tend to be ones that are NOT induced. Do you
understand what induction and inductive coupling is?

Lightning does not have to directly strike the wire for there to be a
surge on it. That is induction when there is no direct strike. If the
strike _is_ directly on the wires, that's different (and has the exposure
of substantially more voltage/current).

Again you did not read what I wrote (what a surprise):
"I intended 'induced' meaning produced by including the most damaging -
strikes to utility lines."

--
bud--