When you make these adapters, be sure you keep the leads as short as possible, use quality cable and connectors, and check the SWR as accurately as possible. Often times just a person standing next to the antenna being checked will change the SWR. Also, it is a good idea to recheck outside of the garage after initial adjustment. A low SWR will make your CB much happier. It doesn't have to work as "hard" due to the mismatch, and you will not be wasting RF energy as heat. High SWR can also cause other problems such as RF in the audio circuits. Normally in the low power CB radio types, it is not noticed, but in higher powered rigs such as ham radio setups, you can get what is know as "RF Bite" from mikes, etc. Hi SWR can also cause distorted audio output due to RF feedback in the audio circuits. This often happens also with "cheap" coax, like that sold by Radio Shack. Good quality coax has a full covering of braid inside, and also foil around the center insulator. Cheap stuff is so thin that you can actually "see thru" the braid. Transmitter power loss is as follows: (these are theoretical losses, and do not take into account any other factors)
1:1.2 .8% loss
2:1 11% loss
3:1 25% loss
6:1 50% loss
Obviously, an 11 percent loss does not seem like much. But when your CB has a 2 or 3 watt output, it may effect the distance performance. Add this to the "foldback" that the finals will do if SWR gets too high, and the loss becomes significant. Hope this helps a little.....