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:
PURPOSE:The N-25 is a passive noise suppressor that employs a high density, low loss toroid 0.25mH choke designed to eliminate in-line noise for Auto-sound, Avionics, and ham radio/CB/Two-Way communication systems including: Alternator Whine, Fan Hums, Dodge Ram Cummings Torque Converter Clutch Cycling Repair*, etc.The N-25 applications include Power Equalizers, Small Amplifiers, Cellular Phones, CB Radios, Two Way Communication Equipment, CD Players, and AM/FM Cassette Decks, etc.
FEATURES:The air-cooled design of the N-25 filter permits maximum efficiency and effectiveness.The ferrite toroid core of the choke component of the L configuration is responsible for a very high rate of attenuation with very low line losses.There are only three wires needed for the installation of the passive filter -Filter Input, Filter Output, and the Chassis Ground.
INSTALLATION:Make sure the noise is in-line before installing an in-line filter such as the N-25.A good confirmation would be to temporarily substitute a 120 VAC to a 12 VDC power supply, or a 12 Volt motorcycle battery, for the vehicle's electrical system.If the noise goes away when the alternate power supply is connected, then you have a case of in-line noise.
To get optimum results with the N-25, the following directions should be followed:
1.Cut the component's main power lead between the fuse and the component.
2. Connect the Green wire to the fuse side. (If there is no fuse, add one --- 10 Amps is recommended)
3.Connect the fused Red wire to the component side.
4.Connect the Black wire to a good chassis ground.
Practical and easy to install, the N-25 is one of the most versatile and effective filters on the market.
Note: The 30-Amp rating is instantaneous = peak… not constant. Fuse the Green lead with a 5 to 10-Amp fuse. Average current draw should be no larger than the fuse size of 10 amps.
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