The ZS6BKW antenna is a better match for our bands than the G5RV. The method of construction and tuning is essentially the same for both antennas but the dimensions are different.
Here is the ZS6BKW antenna installed at AK6R fine tuned for the CW/FT8 frequencies on 40-20-17-12-10 meters. An excellent antenna when installed at 30 feet or higher and no tuner required avoiding the tuner losses and constant retuning. If you want to work all bands from 80-10 install an antenna tuner between the 1:1 balun and the amplifier and ignore the 39/40 switch.
Is this the best FT8 antenna? – I think so as I has made over 70,000 contacts and it still is a proven winner -Good world wide DX, easy to install, no tuner and takes full legal limit.
Here are several different 1:1 baluns you can use depending on power requirements:
Ferrite Snap On, ID = .514in/13.1 mm, 10 Pack for troubleshooting unknown RFi frequencies
Use Mix 31 for 1-300 MHz - 4 pieces
Use Mix 61 for 200- 2000 MHz - 3 pieces
Use Mix 75 for150 KHz-10 MHz - 3 pieces
At last a troubleshooter's ferrite kit that works from 150 KHz to 2 H=GHZ. Now you can suppress RFi from unknown frequency ranges with a full spectrum of ferrite cores that have a 1/2" ID large enough for multiple turns of many common data and signal wires. Try 1 mix and see if it has an effect and if not then try another until you suppress the unknown frequencies. Or use them all to provide protection across a broad frequency range. 3 ferrite cores provide at least 500 ohms in the frequency band to give a measurable difference in RFI and noise suppression.
Square or Hex sided depending upon inventory stock
Here is the Coax Noise Filter used to suppress coax common mode currents (works for all type of antennas)
PDF of ZS6BKW at AK6R Construction Article HERE: My ZS6BKW Antenna