[Amps] Pi Network

[Chris]

Hello,
 
I have a question for the group. I have Jim Hawkins Pi network
calculator and the numbers the program are producing in the Inductor
calculator is not making complete sense to me. I need a little
clarification please.
 
If I enter a Dia. of 3” and a Length of 3” into the calculator blank
field, I get an approximation of 3 turns for the Coil and approximately
1” Spacing between each turn.  My question is that if that’s correct
then why if I add the wire/tubing dia. In inches plus (+) the 1”
spacing, the overall length is now longer then the 3” length that I
originally entered in as the Length?
 
If I am using ½ tubing with 1” spacing then the overall length is now
5”.  From beginning to end of coil in order to make up 3 turns, I have 2
complete turns with 2 half turns at each end of the coil. So I have 2”
in total tube material plus 3” inches of total spacing. Together I have
an over all length of 5” now vs. the 3” length that I originally called
out for?
 
I hope what I wrote makes sense if not I can try and elaborate.
 
One again thanks for the help!
 
Chris