the "18ft coax" is a myth and has been proven as such time and time again. if your "very best cb shops in the world" told you that then i would find another shop, cause they aint.Any CB can be tuned. Some more than others. The plan when you get a cb tuned is to get the lowest dead key possible and the highest swing the radio is capable of. You had swr??? but nothing about the swr. A 4ft fire stick probably will not get you the ideal swr's. You need 18ft of coax to start with and a 8 ft francis in my opinion. I firmly believe that I have one of the very best cb shops in the world here locally. The name of the shop is T.C's Radio in Watha NC just off I-40.His number is (910) 285-5841. He can answer any question you have and may allow you to ship your radio to him. Or allow you to purchase a tuned radio and he ship it to you. He deals cash only! If you call ask for "T" thats what his friends call him.
highly illegal and comes with a VERY STEEP fine if caught. dont know about you but i really dont want to pay it nor lose my equipment to the FCC. there are people out there that WILL hunt you down and report you to the FCC. a "tune" is really a waist of time and money. if you want more power and better range then get your amateur radio license.Everything you said about tuning the antenna is correct. But a CB can be tuned. They are all turned down to meet FCC regulations from the factory. That radio could probably do around 20 Watts. A higher end radio like a galaxy for example can do just over 50 Watts. The trick is to have a good radio man that's knows what a CB was designed to put out and not turn it up past that.
a "cb tune" is nothing more than a waist of money on new radios. older radios "might" benefit from it only because over the years they could have drifted off freq. but other than that there is no need to actually "tune" a cb. now, tuning the antenna is a different story. you want a SWR reading of between 1-1.7:1 on both ch1 and ch40 that will put it below 1.5:1 on ch20(or more correctly the middle of the band). SWR changes with the sweep of the band so having it set as low as you can on 1 and 40 gives you the best possible SWR across the band.