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:
50:50 (1:1) CUBE™ Ladder line to Coax Balun, 1.8-61 MHz, 5 KW, G5RV/ZS6BKW - FREE USA Shipping
The CB-1-5000AT Antenna Tuner Balun is a 50 ohm to 50 ohm, triple core feed line choke designed to provide high choking impedance between a balanced ladder line feed line (zepp, G5RV/ZS6BKW, extended double zepp, etc.) and short 50 ohm coax feed line (to antenna tuner) at a power of 5000 watts PEP from 1.8 to 61 MHz. The CB-1-5000AT is configured as a Guanilla transmission line transformer with balanced outputs (current balun configuration). It is best used when ladder line impedance seen at the end of the ladder line to balun connection is close to 50-150 ohms. Enclosure box is 4″ x 4″ x 2″. Typical choking impedance range is 1K-10K ohms from 1-31 MHz.
Typical ZS6BKW multi-band antenna with CB-1-1500 or CB-1-5000
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