Putting a knot at the very end of the antenna is no big deal. But again, if you never test to failure, you cannot say the knot didn't effect your range. I don't think you understand the logic. It's like you are saying the removal of 5th gear never effected your car's top end becaue you can still go 20MPH. My point was your range check method could not indicate that "alls fine" since you really don't know how you impacted your range. You just checked to 75 feet. I'm not picking on you or anything like that, but in general IMO it is bad advice not to check to failure at least once. This may not be a big deal for the type of models you fly, but it still should be done occasionally. It can give you a good heads up that all is not well. For example, if you normally fail around 200 feet, and then all of a sudden one day you start failing at 100 feet... something's up. A normal 75ft ground check may not pick this up. Now I don't suggest that you test to failure every time you fly, I don't. For daily flying a quick go/no go test out to X number of feet is fine. However, please note that different radios have different minmum ground range procedures and distances. Consult your manual. Cheers!