Aren't proven theories then referred to as physical laws?
73
Roger (K8RI)
On 1/12/2015 12:58 PM, Jim Brown wrote:
On Mon,1/12/2015 8:36 AM, greg greene wrote:
the difference between
theory and practice - is the difference between theory and practice'
what
he meant by that was that theory is the guide - practice is result, when
the two don't match - review both. Theory is never 100% - that is
why it
is theory
The word "theory" here is misapplied. Somehow, we in the radio world,
long before most of us became hams, divided the FCC exam into a
written exam, which was CALLED "theory" and the CW exam. What that
exam covered (and still does) is a combination radio Rules, operation,
and fundamental physical principles. NOT unproven "theory."
Human understanding of how things work has been well known for a LONG
time. Nearly 100 years ago, Bell Labs published the concept of the use
of feedback to reduce distortion in amplifiers with a corresponding
reduction in gain. The fundamentals of transmission lines and
antennas are also that old. Before that work was proven by disciplined
experiment, it could reasonably be called "theory," even though it was
clearly proven by the math.
- the more we observe the results of practice - the closer we get
to redefining the theory, and then the closer we get to refining the
practice.
Jim Garland addressed this quite well in his post. REAL components are
not ideal -- inductors have series resistance and parallel
capacitance. When we look at a circuit diagram that shows an inductor
and ignore that fact, WE have failed to apply fundamental principles.
This is not a failure of "theory" nor those principles. Likewise, when
we look at a resistor and fail to see it's self inductance (and even
parallel capacitance), and look at a capacitor failing to see it's
series and parallel resistances and series inductance, it is WE who
have failed, NOT "theory" -- those fundamental principles. And, of
course, active components -- tubes, transistors, and diodes also have
strays.
I was trained as an EE, and spent much of my life in the field of
"engineering." Real engineers are trained to understand the whole
picture, the strays, the costs of eliminating or reducing them, and
when to stop with "good enough." We don't need, nor can we afford
"ideal" -- we must work with the real estate that our home sits on,
with the sky hooks that are on it, and cash in our bank account to
build antennas that "work."
Inside our radios and amplifiers, we must look for and understand what
Henry Ott calls "the invisible schematic hiding behind the 'ground'
symbol," as well as the complete schematic that includes those stray
Rs, Ls, and Cs. Failure to do that is OUR failure, not "theory," those
fundamental principles.
Understanding HOW antennas work allows us to achieve a better result
faster. Sure, we could build a dipole, operate it at various heights
in increments of 5 ft, and use a drone with instruments attached take
a lot of measured data to see it's directional pattern, both vertical
and horizontal. Bring a very fat wallet to this process. OR, build a
model of that antenna in NEC and have it compute the 3D pattern at
various heights in increments of 5 ft. I've done that in a day or so.
I now KNOW, in dB, the value of 10 ft of additional height on 80, 40,
and 20M. That work, BTW, is on my website.
http://k9yc.com/VertOrHorizontal-Slides.pdf
73, Jim K9YC
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