I did some tuning of my ZS6BKW antenna just before the 2012 ARRL CW Sweepstakes contest. My goal was to get the SWR in the CW Bands down to 3:1 or better. The reason I wanted this was that the internal tuner on my IC-7600 can quickly tune that range, without the need for my external LDG tuner. The 7600 also can automatically retune the antenna when needed once the CW key is pressed. With this function and the internal tuner memory, I was able to move very quickly between Bands during the contest. The antenna did a great job for a basic wire antenna. I will surely be using it in the future and may put up another one at a different angle.
If you want to see the data, here is a file with the SWR data tabulated over all the HF ham Bands. Remember, this antenna does not cover 15 meters or 30 meters. Here is the file – SWR Data File
I still plan to do a little more tuning of the antenna to try and cover more Phone Bands within the 3:1 SWR region, but only if I can do so without knocking any of the CW Bands out of the range.