As to a question I asked earlier.
Why is a tuned circuit sometimes called a tank circuit?
This is a term that goes back more than 100 years.
Any guesses?
73
Bill wa4lav
________________________________________
From: Amps [amps-bounces@contesting.com] on behalf of Roger (K8RI)
[k8ri@rogerhalstead.com]
Sent: Monday, January 12, 2015 11:40 PM
To: amps@contesting.com
Subject: Re: [Amps] The genius of ham radio
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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