[TowerTalk] Insulated wire, theory

[KD7JYK DM09]

On 9/21/2022 12:26, Tom Osborne Sr. wrote:
> Can't we just put up an antenna and see where it is resonant and adjust it
> accordingly?

I must admit, I got lazy a few decades ago, and started to look at the 
insulated/uninsulated velocity factor, and relative permittivity charts 
in the radio handbooks, figuring everyone else after a few months of 
experimentation had it right for the previous century to century and a 
half, or so, and save myself the few minutes of figuring it out on paper.

But, just in case, I add about 3 inches on HF, then fold back if needed, 
rather than cut.  No point in being completely foolish, I still find it 
hard to stretch wire adequately.

I've thought about the analysis software on and off, mostly off, as 
having been into computers since the late 70's, it would be yet one more 
gimmick of the week to try and learn, and I'm not sure I've got enough 
brains left for that.

Anyway here's some info, upon which the programs will be hopefully 
correctly written:

Definition, with examples:

https://www.britannica.com/science/permittivity

More in-depth, with examples, and some formulas:

https://en.wikipedia.org/wiki/Permittivity

The above should help one to know if the whatever program they choose is 
close, and worth a second shot.  To avoid confusion, don't look up the 
definition of "theory".

Kurt