|
nec simulation - unexpected result ??
Richard Harrison wrote:
An antiresonant circuit is defined: "Antiresonant circuit - A parallel-resonant circuit offering maximum impedance to the series passage of the resonant frequenccy." The traps in a trapped dipole are antiresonant. -- 73, Cecil http://www.qsl.net/w5dxp |
nec simulation - unexpected result ??
|
using coax shield to create a loading coil ?
It is hard to visualize exactly how these crossovers happen on a
microscopic scale, but the physics of the skin effect dictate that it *must* happen somehow. Theory: "...the physics of skin effect dictate that [it] *must* happen[*]somehow[*]... Now, compute the consequences of the theory to see if it is right what it would imply. Compare those computation results to experiment. If they disagree, the theory is wrong. If you can't apply this procedure, your statement cannot be verified scientifically. |
using coax shield to create a loading coil ?
Mike Speed wrote:
It is hard to visualize exactly how these crossovers happen on a microscopic scale, but the physics of the skin effect dictate that it *must* happen somehow. Theory: "...the physics of skin effect dictate that [it] *must* happen [*]somehow[*]... Now, compute the consequences of the theory to see if it is right what it would imply. Compare those computation results to experiment. If they disagree, the theory is wrong. If you can't apply this procedure, your statement cannot be verified scientifically. Rubbish! The word 'theory' has two different meanings - so different, they are almost the opposite of each other. And you are using the wrong one. You are using the layman's meaning of 'an unproven speculation' - but in science, the word means almost the exact opposite. A scientific theory is "a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena" [1]. (In scientific language, an unproven speculation is called a hypothesis or a conjecture. It is specifically *not* called a theory.) A *scientific* theory explains the underlying reasons for a huge number of different experimental and practical observations, so that they all mesh together and support each other. Theory supports observation; and observation supports theory. Equally important, the outside edge join up seamlessly with the theory and observations about related areas of science. This means that scientific 'theory' is vastly more than mere speculation: it has the power to predict what will happen in cases we haven't even looked at yet. As I said, the crossovers between strands of braid are hard to visualize and predict in detail - but that is entirely our problem. Our lack of understanding doesn't change the way things work. There is no absolute proof that the skin effect will apply to braided strands, but this is only a very small gap in our knowledge. At both sides of that gap are situations where we're completely certain it does apply. Moreover, there is no rational reason to suppose the skin affect might fail to apply to braided strands. Based on that solid body of theoretical and practical knowledge about the skin effect, it only needs a very small amount of additional speculation to bridge the gap in our knowledge about braid. Applying what we do know to what we don't, it immediately gives us a clear and simple explanation why the RF resistance of braid is greater than a smooth surface, and why it increases dramatically when the braid is corroded. This is a perfectly normal application of scientific logic to bridge small gaps in our knowledge. Since nothing can ever be proved in absolute terms, I must philosophically decline your challenge to waste time on modeling it in detail :-) In terms of strict logic, the onus is on you to find a way to disprove it and to offer something else in its place. Good luck with that. [1] http://wordnet.princeton.edu/perl/webwn?s=theory -- 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
using coax shield to create a loading coil ?
Ian White GM3SEK wrote:
Our lack of understanding doesn't change the way things work. Neither does our understanding. :-) -- 73, Cecil http://www.qsl.net/w5dxp |
using coax shield to create a loading coil ?
Mike Speed wrote:
Rubbish! No, it isn't. That was a paraphrase from, "The Character of Physical Law," by Richard P. Feynman, page 156, half-way down. Also from "The Character of Physical Law," bottom, page 156, "It is scientific only to say what is more likely and what less likely, and not to be proving all the time the possible and impossible." Therefore, it is more likely what Richard P. Feynman said about scientific theories is right and what you said about scientific theories is wrong. Here's a clue: if even Feynman needed a whole book to cover the subject, is there any possibility that your "paraphrase" from half-way down one page might be incomplete, inaccurate or misleading? The rubbish arises entirely from your habit of snipping bits from here and there, and quoting them out of context. The history of this thread shows that each time someone makes a considered reply, bringing back the whole context, you snip it all out again. Enough of that game. -- 73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
| All times are GMT +1. The time now is 03:30 PM. |
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
RadioBanter.com