You can use translate.google.com and type in the url into one side with "detect language" and click the url on the other side and it translates the page <-hot tip of the day lol
Lots of articles on the fuchs antenna, aka: half wave end fed. Plenty of info on the transformer design and plans on tapped and isolated EFHW antennas.
I am currently building my own.. well I did a while back but want to improve. My original used a 1:9 impedance transformer on of all thing a ferrite bar from an old AM radio. It worked surprisingly good and gave a 1:1 SWR across most channels but now I realize my SWR meter was false as the permability of the ferrite was taking up wasted power instead of reflecting power. Moved on to the original fuchskreis antenna match box and it worked great but was quite narrow band, the other trade off of efficiency I guess. Bought some 130-2 torroidal donuts and wound a few transformers and they work well with the off center tap (16 turns, tapped at 3rd turn) but they are very broadband which leads me to believe they are lossy too, but for field CBing they will probably perform a ton better than shitty whip antennas or firesticks.
Now I am building a huge 1:8 ratio transformer out of heavy copper house wire. Stripped it down and wound a coil for 16 turns around an inch diameter. Tapped up on third turn and it easily pushes a 50 ohm load into 3500 ohm load.. dipole end fed. It's far more efficient than anything else I have tried.
Anyway, don't mean to digress... check out that site. Plenty wealth of information to be found. Wish we had this sort of creativity here in the US but seems everyone is stuck on a smart phone. Translation isn't perfect, I think "spotlight"="impedance" and a few other words are goofed, but easy to recognize.
The quiz questions to join the group were weird, but I think the moderator is looking for human answers to confusion, or at least I got an oddball question. It's worth adding to your groups though if you are on FB, tons of info on EFHW antennas.
So why am I suddenly interested in end fed antennas? Small property really. They allow for taking the most bang for the key up. All it takes is a wire draped around and trimming it for best SWR after a match box. Just stay away from those 9:1 auto-transformers. They are built with ferrite and only match up to random lengths of wire.
Real end-fed designs are resonant and have high step ratios to get 50 ohm feed line to 2000-5000ohms. The fatter the end fed half wave radiator the lower the ohms I have read.
Thus throw up some pipe into the air, insulate the base, or drop wire from a tall structure, make it inverted V, vertical, horizontal, whatever radiation pattern you want, load it up with a RESONANT tuner, be it L, PI, fuchs transformer, voodoo, or worse case the auto transformer 1:4 to 1:10 transformer with all the loss in toroid heat... point being try end fed antennas. Remember current is in the middle of a dipole, voltage is at the ends. If you can't feed a dipole center at nominal 50 ohms that is practical for our rigs, then use a transformer or match to feed it on the voltage end where it's 2-5k ohm. Loss in transformation is usually under a decibel, much less than your coax probably, and you can mount it vertically at THE END.
All the calculations on that page are correct. I'm currently building the "MONO BAND HIGH EFFICIENCY HALF WAVE ANTENNA" at the bottom of the page using a T130-2 core since I got a pack of 4 on Amazon for a few bucks. It works equally as good as the open air wound coil autotransformer version I built but is far more compact and less sensitive to surroundings so I am actually sticking with it for my permanent install and might make another for a camping antenna match box.
Getting the coil and capacitance correct is the hardest part with an L match for EFHW antennas if going this route, but sticking to the chart on that site comes real close. I ended up using 14 windings on a T130-2 and around 14pF coaxial capacitor to resonate around 27.3MHz where I want to be at (I like higher CB channels and 10m use).
After an insane amount of time trying to get an L match to work like in the link provided previously I gave up I got so frustrated because on the bench my T130-2 coil and coax capacitor was matching into a 3.3K Ohm resistor perfectly. I had tuned it to 27.2MHz and the SWR was 1.1, barely even moved the meter needle until band edges. Went to put it up on the tower with antenna 1/2w pole and shit hit the fan. Could not get that damn thing to match no matter what I tried. My neighbor probably thought I had gone insane climbing the tower up and down all day to modify pole length and match box position. Best I could achieve was 1.8 SWR on channel 1 and 2.2 on channel 40. Tried recutting the coax capacitor, fiddling with the toroid coil position, testing the match box live on the permanent coax run, cursing to the Gods... so on.
Went back to the original Fuchskreis EFHW resonant match coil and it worked fine.. go figure. I don't know what the hell was wrong with my L match but it was one of those hair pulling experiences where something on the bench worked as good as textbook examples, but when deployed in the real world failed horribly. Spend a whole day on that bullshit.
Original Fuchs 8:1 coil just works, hard to screw it up. I am still using air wound version for higher Q with the primary wound center of the secondary like.. m0ukd.com/homebrew/baluns-and-ununs/end-fed-half-wave-antenna-tuned-coupler-efhw/ Another good link by the way. I placed my coil winding closer for a little less loss but this just works without any fuss. I use a tuned coax capacitor instead of the variable air capacitor for my permanent install on 11m CB band.
I actually posted this to vent. Nothing sucks more than spending a whole day or two working hard on perfecting something only to have it fail miserably and end up going back to the old design feeling defeated ugh.
And back up the antenna goes. With the original Fuchs matchbox coil/cap I am getting 1.3 on channel 1 and 1.2 on 40. Around channel 30 I barely budge the meter even with it cranked beyond calibration. This is with full power out of my Anytone Smart CB (Albrecht AE-6110) at 8 watts. Covering well between 26.8MHz to 27.8MHz with the highest SWR around 1.5 on the edges. Of course I could still transmit further out of band to cover 12m or 10m band but my main interest is CB and maybe some outband stuff when skip comes in. Now time to upgrade my rig to an SSB unit. I miss SSB so much and haven't had a radio with it since my Cobra 148 when I was a kid and stupid and sold it for pennies to some jerk that swore it was a crappy radio. You live and learn lol.
Looks small but that's actually a 17' antenna above the insulator PVC on a 20' of tower. Coax is RG8/u and the matchbox (bottle) is the size of a cola can lol. The whole antenna is lightweight conduit pipe, I slid the top piece into the bottom and used a pipe clamp to test for best SWR, once found I drilled through both a foot down and bolted them together, thus the visible electrical tape towards the top of the aerial in the photo, PVC as the insulator between that and the bottom conduit pipe which is 1 1/2" diam. Yes PVC is awful but I made sure to pick the thickest and it handles winters and summer storms well. Everything is waterproofed too with RTV silicone and lots... LOTS of electrical tape, the self sealing kind Gets the job done. Time to get on 27.555USB hehe.
I've built end fed half waves for up to and including 80 Meters by feeding them with a 1/4 wave matching stub of ladderline. I think you can do the same with a .64 wave wire by shortening the stub until you get a match.
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I got so frustrated because on the bench my T130-2 coil and coax capacitor was matching into a 3.3K Ohm resistor perfectly. I had tuned it to 27.2MHz and the SWR was 1.1, barely even moved the meter needle until band edges. Went to put it up on the tower with antenna 1/2w pole and shit hit the fan. Could not get that damn thing to match no matter what I tried. My neighbor probably thought I had gone insane climbing the tower up and down all day to modify pole length and match box position. Best I could achieve was 1.8 SWR on channel 1 and 2.2 on channel 40. Tried recutting the coax capacitor, fiddling with the toroid coil position, testing the match box live on the permanent coax run, cursing to the Gods... so on.
Gets the job done. Time to get on 27.555USB hehe.
