In a message dated 11/22/03 11:04:13 AM Eastern Standard Time,
jimlux@earthlink.net writes:
>>I think it's best to leave it at:
Loading coils are not isolated lumped elements and cannot be modeled as
such.
A lumped model serves as a decent design tool to determine a starting point,
which will have to be further iterated empirically.
To give credit where it's due, the research work I've described above was
primarily done by Terry Fritz (in the US), Paul Nicholson (in the UK), and
Antonio Carlos M. de Queiroz (in Brazil). I can come up with some links to
papers if needed.
Jim W6RMK<<
Very interesting info on Tesla coil research, thanks.
There is interesting discussion of the phenomena and modeling by W4RNL on his
web site:
16. Notes on Reactive Antenna Loads and Their NEC Models:
D. Some Solenoid Loading Basics
L. B. Cebik, W4RNL
http://www.cebik.com/amod/amod16.html
where he states the following and then goes into the case of modeling real
life helix and investigating its property and NEC modeling.
>>As a consequence, few modelers have explored the behavior of helically
wound single layer solenoid inductors in their models--simply because winding a
coil is too laborious a task relative to using the loading facilities built
into
NEC. We have presumed that the loads--especially Type 0 series R-L-C
loads--adequate specify the loads we need.
Yet nagging suspicions remain about such loads. The current differential that
is present at each end of the load suggests that--like their linear load
counterparts--these loads do not act like pure inductances, but may also
function
as simple current bearing wires. Models of helical dipole elements show very
usable gain, which parallels the experience of those who have constructed such
antennas. I guess we shall not know whether mathematical models of loads
accurately reflect the operation of single layer solenoid inductances unless we
actually wind some model coils and replace the Type 0 loads with them. <<
Yuri, www.K3BU.us
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