On 1/28/2020 2:13 PM, jimlux wrote:
The K-factor graph can be derived semi-analytically - there are several
analytical expressions for the complex impedance of an antenna (and you
can solve for where X is zero) over a restricted range. Or, you can
numerically integrate the field equations - which is what people have
been doing since the late 1800s.
Some of the math Jim is describing here is advanced college level. When
we encounter design formulas, like the the Handbook, they are the result
of having written and solved those complex equations. And often, the
formula is a simplified version, based on certain simplifying
assumptions (for example, that the wire is straight, round,
un-insulated, and not close to other conductive objects). A more complex
equation might take into account the effect of insulation, the effect of
height above ground and the quality of the soil.
Modeling programs like NEC use various techniques to solve the
fundamental equations for data that we enter.
73, Jim K9YC
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|