Ok, here ya go. Visit the three links and you will notice a common way of winding the ferrite toroid with a 2 turn twisted pair primary then 7 turns then a cross over and 7 more turns.
To make a very small version that will easily handle 100w SSB and work down to about 5MHz use an FT-114A-43 ferrite toroid. For one that will handle up to about 400w SSB and down to 80m use an FT-240-43 core and for up to about 800w use 2 stacked FT-240-43 cores.
You can use various sizes and types of wire but enameled magnet wire is the easiest to work with. I think #20 to #18 wire is fine for 100w and I use #14 for the 800w version.
The 100 to 150pf capacitor goes across the 50 ohm input and doesn't see the super high voltage at the transformer output but I would use a capacitor rated at least a few hundred volts for the 100w version and at least 1kV for the 800w. The value is not very critical and only comes into play on 10m.
Once you make the transformer attache 1/2 wavelength of wire at the lowest frequency you want to use, like about 63ft for 40m and trim for a good match in the middle of the 40m band. You will then get a great antenna for 20, 15 and 10m, however 10m will resonate higher than the SSB phone portion because 7.2MHz X 4 = 28.8MHz.
If you make one for 80m phone it will be out of band on 40, 20, etc because 3.9MHz X 2 = 7.8MHz and so on. One way around this is to make and tune a 40m version with provision to attach more wire using an automotive butt connector, then add another 60 something ft to resonate where you want on 80m and jumper the 40m insulator when you want to use 80m. Or add a 40m trap at the end of the first 63ft of wire then add an element for 80m and it will play just fine. I recently did this to one of mine and it works great and I get about 3.8 to 4,0MHz at the 1.5:1 points plus the entire 40m band and so on when the antenna is set up in the CA desert. In some areas around town the match is a bit worse and probably affected by its surroundings.
The antennas shown in the links are basically the same as the Hy End Fed and the MyAntennas but much cheaper. These sometimes get confused with the generic 9:1 balun types and they are not and work much better!
prcguy
https://forums.hamisland.net/showthread.php/21993-The-multi-band-end-fed-antenna-with-a-twist?
PD7MAA HOMEPAGE: Multiband end fed antennas 3.5 - 30mHz
https://pa3hho.wordpress.com/end-fed-antennes/multiany-band-end-fed-english/
yep, prcguy...could you post info on building EFHW that doesn't require a tuner
