On Thu, 3 Jan 2008 20:56:02 -0500, "AI4QJ" wrote:

Jim's question is answered quite simply and you have offered one
yourself, generously slathered with doubt about its obvious
application.

However, my guess finds the symptoms would be more aligned with two
current nodes, not voltage. However, voltage or current, either mock
the notion of "traveling waves," as Cecil recoils in shock from the
bitter reality (his bête noire when it fails to serve his agenda) of
this contradiction.

No it doesn't. As soon as heat is dissipated, then we know that there is a
real power component where current is in phase with voltage.

Hi Dan,

That stands to reason.

I think in this
case the insulating material broke down due to high voltage.

However, that does not. You (and I) don't have enough information
(not that it matters in confounding Cecil).

The reason is
that, with an unterminated coax, the reflected wave adds to the forward wave
only at those portions of the line where the standing wave was at maximum
and minimum.

This is rote (aside from the rough and loose description).

If the linear amp had a forward component at Vmax = 6KV, then
the standing wave maximum and minimum would be +12KV and -12KV.
and this is the particular information neither of us has. How do you
know Jim was running a linear, much less resulting with that
particular voltage? The clipped voltage commentary is strictly
conjecture.

Your theory on the other hand, though possible, is lees likely in an amateur
environment. The reason is that even a 22 AWG conductor can withstand a
rather large amount of current before it gets so hot as to melt and damage
the thermoplastic insulation.

Fusing current for 22 AWG runs about 40A in ambient temperature. The
inner core is not in ambient, but rather it is insulated (as you well
testify), which lowers the current required to open it. We don't need
fusing current but it does establish a rather dramatic caloric upper
limit that easily exceeds the capacity of plastic to sustain exposure
to the obvious heat. It is enough to say that lower currents could
easily melt the plastic without having to "blow the fuse" so-to-speak.

All that remains is additional information from Jim as to the physical
clues of melting or carbonization. With thermal runaway a distinct
probability, both probably occurred and it is then a chicken and egg
problem. The wavelength distance of these burns from the open end
will nail it down with far more assurance than anecdotal evidence.

It relates to another bitter round in his own thread of trying to
explain the confusion Hams have with Rhombic antennas and traveling
waves to then discover standing waves line up and down them:

In any antenna, you will have a combination of standing waves and traveling
waves.

It took me only one post to prove that with data. I am not
responsible for Cecil's framing of the argument to the contrary. Most
of Cecil's craft projects contain critical errors that collapse his
argument into wandering statements. To this point of 400 postings, or
so, absolutely no one has expressed any confusion that Cecil implied
was his premise to explain in the original thread. His straw man
kneed him in the groin before he could get in his first argument and
the gasps of incredulity were his own. :-)

What I was saying was, in the above example, even if you started out
with an open coax line and a perfect standing wave where no real power was
dissipated, immediately after the insulation broke dow real power started
dissipating and that component could only be composed of travelling waves,
in phase with current and voltage.

It isn't that difficult, complex, or messy. All of this embroidery is
like a traffic cop stopping you for speeding, and citing your
violation in terms of galactic spin (tracking you at an even speed is
vastly simpler and both you and the judge would be forced to agree
that, yes, you were speeding).

73's
Richard Clark, KB7QHC