"DEAD ON" hmmm
what exactly are you trying to say bighammer???
the answers are right there in the link you posted 
QUOTE
"Another use of the length of a radio signal is in using transmission line sections (1/2 wave, 1/4 wave, etc.) in order to provide various impedance transformations"
if you use the halfwave calculator to cut several different brands of lets say rg213u then i can absolutely guarantee you or anybody else that it will NOT be "DEAD ON" as i tried to explain earlier,
if you take the published vf for a particular coax as fact and use that or any other calculator to determine the EXACT correct length then you are guessing the velocity factor,
if you have the means to accurately measure the vf then you dont need any program,
let me have another go at this,,
an electrical halfwave of coaxial cable will mirror the terminating/load impedance ( your antenna ) at its source end ( the radio end ) regardles of the load impedance,
assuming we are dealing with 50ohm coax AND a 50ohm source ( your radio again ) and ignoring the naturally occuring increase in loss and return loss due to increasing coaxial length,,,,,,,,,,,,,,,,,,,,,,
cutting electrical halfwaves does 2 things,
it allows you to see the actual terminating impedance at the source when the load IS 50ohms and when the load is anything OTHER than 50ohms,
IE it will not transform a 75ohms load impedance to something other than 75ohms as seen by the source ( your radio )
it also allows you to add or remove electrical halfwaves of coaxial without upsetting the impedance as seen by the source,
IE you can take your radio from the shack add however many extra electrical halfwaves of coax it takes and go sit watching tv with the wife without upsetting the impedance seen at the source when the load IS 50ohms AND when the load is anything OTHER than 50ohms,
if the load is exactly 50 ohms then it does not matter what extra length you add/remove the source will still see 50ohms,
putting it more bluntly
"IF and only if your radio AND antenna are "DEAD ON" 50ohms and you got 50ohm coax then COAX LENGTH DONT MEAN SHIT"
now please explain exactly what you think you are achieveing by cutting your coax with a computer program that makes it "DEAD ON" because i just dont get it.
