A couple of people have asked me for the end fed antenna plans, so here are a couple of links I used when making them. The wide band 64:1 transformer can cover about 3 through 30MHz depending on the ferrite core type, size and number of cores used.
You attach a wire 1/2 wavelength long and the transformer matches it very well to 50 ohms, and it will also cover many harmonically related bands higher in frequency than what you cut the 1/2 wavelength of wire for. Most of the ones I make have about 63ft of wire to cover the 40, 20, 15 and 10m bands, all without a tuner. I have used the same transformers with about 16ft of wire to just cover the 10m amateur band and a little more wire around 18ft will cover the CB band. There is not much difference between this antenna and say an A99 in that you are exciting an 1/2 wavelength radiator with a matching network to 50 ohms. The difference is an A99 has a very narrow band matching circuit only designed for the CB band and this end fed transformer is very broad band.
Its recommended to have a good common mode RF choke in the coax not too far from the transformer to eliminate any RF on the feedline, and in my experience there is no detectable RF on the feedline unless you operate the antenna outside its resonant range.
Here are three links I refer to when making the transformers:
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/
For up to 100w SSB or maybe 30w key down AM I use an FT-114A-43 ferrite core. For up to 400w SSB or about 100w carrier I use a single FT-240-43 core. The 100w version is nice because it will fit in a plastic box a little bigger than a Zippo lighter. I've made some versions that handle about 1kW but on lower frequencies than CB and I would have to experiment to see what core is best for that much power on CB/10m. I suspect a pair of FT-240-61 cores would be a starting point if you need high power.
You will notice the common theme in the three links where they wind the transformer with 2 turns of a twisted pair for the transformer primary, then 14 turns for the secondary and they cross over the core and reverse the windings on the secondary after 7 turns. You have to study the pictures in the links very carefully to note how the crossover is done, otherwise it doesn't work.
The FT-114A-43 core is about $2 and the FT-240-43 core is about $9. For a version that will easily handle a stock CB or up to about 100w SSB, by the time you buy the core, a small plastic box and some wire and a chassis connector, you might have $10 in the antenna. And it will perform as good if not better than any 1/2 wave base antenna out there.
For a really good common mode choke for the CB band, get an FT-240-61 ferrite core and wrap 8 turns of RG-58, RG-8X or better yet, RG-142 coax through the core. Its probably best to do 4 turns then cross over and reverse like the transformer is wound, but just wrapping 8 turns through it will make a fantastic choke targeted for the CB band. You can simply use the coax running to the end fed antenna and wrap it so the choke is 5 or 10ft down the coax from the end fed transformer.
Once you have the transformer and end fed antenna working and if you decide to get an amateur license, the same transformer will work 40 through 10m depending on how much wire you use. For CB use you generally want to hang the antenna vertical and a tree will work or a telescoping fiberglass mast makes setup and take down easy. For skip on CB or for the lower amateur bands I use them horizontal about 15 to 30ft off the ground depending on whats available to hold them up.
Now you have some plans, so go make an antenna.
prcguy
Edit: For the transformer wire you can use enameled transformer wire or you can use Teflon insulated (its a pia because it wants to unwind) or for low power like stock CB a strand of wire from CAT5 Ethernet cable is great because its insulation has good RF properties. When winding the transformer its best to make the first wind, then push the next winding through with your finger with wire near the last winding then pull the remainder of the wire through the hole rather than sticking the end of the wire through the hole and pulling the rest through. This makes the windings tighter against the core.
