Gentlemen, the proof is in the pudding.
Laying aside the formulas and "mumbo jumbo" as some said, my illustration was to simply demonstrate that if this 18 feet coax thing was actually true, then, it would be true for ALL frequencies. That would mean that for EACH band, or frequency, you wanted to use, you would cut a piece of coax a specific length, some of which would be as much as 60 feet long at 3.9 MHZ. OR at 1/4 wave 234/3.9+ around 30 feet----WHATEVER multiplier you think is best, have at it, have a ball! Impress some newbie. Don't WORRY about VF--and, besides, even if it made any difference, you would still would come about at about the same place! WHERE would you put TEN lengths of coax up to 60 feet long in an S-10 pickup--drag it along the ground behind you! :twisted:
The screwdriver takes CARE of it and does it at about 1.2 -1.5 SWR (not "swr-zzzzzzzzzzzzzz"), so WHAT'S the big deal? IF it WORKS, it WORKS! And it DOES work! FOR THE MULTIBAND OPERATOR, IN ANY CASE, IT DOESN'T MATTER!!!!!!!!!!!!!!!!!!!!!!!!!!! I and thousands of other hams have NEVER even given COAX length a second thought, indeed, never ever HEARD of such----until we heard it from the CBers!
And I have installed hundreds of HF radio systems by rolling out how much coax it took to get from the radio to the antenna, tuning the ANTENNA (not the dumb coax), and FORGOT about it.
So as LONG as I can DO that, it WORKS, it will still remain----a CB Myth and Legend like "if I double my power, I'll get double the distance"!
RR