On Mon, 22 Mar 2010 18:24:06 -0700, "Joel Koltner"
wrote:

What are the significant loss mechanisms that he's not accounting for? (He
claims his matching network isn't getting at all hot.)

Hi Joel,

Your source is thrashing against a number of conventions that he has
disproved by relying on Schopenhauer - what a wheeze! This is the
same argument that "revolutionary" thinkers appeal to forgetting that
their theories can be dismissed by the same mechanism.

Let's examine this heuristically (irony there). Two observations
provided by your source raise the temperature of
1. a can by 100 deg C with 100W;
2. a tube by 100 deg C with 150W.
Heat is always concerned with mass and surface area, and heat transfer
is expressed in Watts per square Meter. Temperature rise is expressed
in joules for specific heat capacity and mass.

The two examples provided by the source differ by -50/+100% in heat
transfer. How does this impact the development of a "new theory?"
Let's revisit the two examples normalized to transfer:
1. the can exhibits 127W/m²
2. the tube exhibits 57.7W/m²
Such discrepancies are meaningless? I assume so, because the source
doesn't respond to answering them.

There is, of course, a very simple explanation that heuristics reveals
in specific heat capacity (a term completely absent from the
discussion of heat in a radiator).

Let's consider the nearly 1m loop with a heating wire inside -
curiously unspecified for such a "scientific" and unbiased report. It
is, in fact, an 18ga wire of 80% nickel and 20% chromium (yes
nichrome) which by the current supplied heats up to 550 deg. C. These
details must be immaterial to the original source that ignores them.

Could one imagine a heater wire at 550deg. C heating the outer tube by
100 deg C only? Well, let's consider that light bulb in the can that
exhibits double the heat transfer. It's filament is running at
somewhere between 2200 and 3000 deg C for the same temperature rise.
Nature must have some curious law of heat plateau in this "new
theory."

If we were to rely on heat reportings alone to carry the logic, then
this vast wobbly range of -50/+100% reported values is not very
compelling. Intuition is often appealed to in these pages (some call
it heuristics); and it would seem that the heated wire, with 150W and
supporting 550 deg C would eventually melt the antenna components.
Where else is the heat at that temperature going? It is entirely
contained by the copper tube. Yet our source does not reveal this -
and ironically points out that would be the fate if RF could raise
temperatures.

However, temperature is NOT power. How much power would it take to
raise that specific 83 cm diameter looped 10 mm copper tube 100 deg C?
The answer is 2.16 W-Hours. The 550 deg C hot wire is
running at 150 W continuous and only pumping
up the temperature a paltry 100 deg C.
That is pretty pathetic.

The answer is ALSO 7800 W-Seconds.
Clearly 150W for several seconds wouldn't
make a noticeable heat boost.
That is pretty pathetic too.

Obviously heat rise is a product of time (the term "rise" demands
this) and yet throughout this source's "scientific" and unbiased
report time measurement for these heat readings are wholly absent. How
many in this forum recognize the duty cycle of a typical QSO in this?
How many antenna failures follow from heat, how many QSOs still suffer
from poor efficiency?

For those who care, the formula is simple:
Q = m · C · (Tf - Ti)
where
Q is joules
m is mass in grams
Tf is final temperature (K or C)
Ti is initial temperature (K or C)
C is specific heat capacity in
J/(K · g)
or
J/(C · g)
and for copper is 0.39

For comparison, water's specific heat capacity is 4.18, more than ten
times higher and thus more power is required to raise water that same
100 deg. and this is why water is used in radiators. Mineral oil runs
about half that (and folks struggle to obtain transformer oil for
their dummy loads when water is superior).

An aluminum tube at 0.90 is thus going to run cooler than copper when
we put a heater wire inside (for the same, unstated, time interval).

Given the inordinate number of facts missing, undisclosed time
intervals, no discussion of heat capacity (in a heat report) and the
obvious cynicism cloaked in "heuristics, science, and unbias" -
further reading on other topics has every chance of being equally
blighted.

To put icing on the cake, I am astonished that the original source can
only eke out low 90s percent efficiency in the 20M band! To employ
the original source's arguments: Put 450W to that sucker and tell us
where the 20 to 30W were lost. As it takes only 2W-Hr to raise that
antenna 100 deg C, that air cooled dummy load must be boiling rain and
burning fog.

--- and then again, maybe I did the math wrong.....

73's
Richard Clark, KB7QHC