Ultimate UL Portable Resonant Antenna Build - DIY Micro End-Fed Halfwave Matching Unit

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  • เผยแพร่เมื่อ 5 ก.ย. 2024
  • Call it the End-Fedz Trail Friendly killer if you like. This thing is much smaller and lighter, and a perfect match for the Mountain Topper series radios when you build in some traps or links.
    Needed Materials:
    - Special BNC connectors: amzn.to/38riPF7
    - Toroids for this project are FT50-43: amzn.to/2NU7vbc
    - Capacitors are 100 pF SMD ceramic 500V or 1kV models.
    - 28 ga magnet wire: amzn.to/2AyjpEI
    - Poly-Stealth 26 ga antenna wire. I've ordered from this company a few times and had great service: www.amateurrad...
    - 5 minute epoxy: amzn.to/2ZAAFRZ
    - 5/8" or 3/4" heat shrink tubing (adhesive lined preferred): amzn.to/2VK5Rgq
    - 3/32" or 1/8" heat shrink tubing: amzn.to/2NTnKFp
    Please share your results with me in the comments below, or via email. Have fun with this one!
    73 de K6ARK

ความคิดเห็น • 330

  • @djsomers100
    @djsomers100 3 ปีที่แล้ว +29

    In the middle of a sleepless night, I came up with three ideas that make this build MUCH easier.
    1. Instead of trying to solder the twisted tap off the toroid to the center terminal of the BNC (crazy hard), solder a short piece of toroid wire to the center terminal and then when you place the toroid over the BNC, you can solder the short "jumper wire" to the tap instead. Crazy easy.
    2. Before soldering the antenna stub wire to the toroid, I thread it down through the center post of the BNC. Way easier than soldering the wire to the toroid and then snaking the antenna stub up through the center post. After you have threaded down, you can strip the end of the wire, and place toroid over the BNC, and solder the antenna stub to the appropriate toroid lead.
    3. Use Liquid Electrical tape to provide insulation over your solder points rather than heat shrink tubing. It is much lighter, thinner, pliable and easier to work with than heat shrink.
    Hope you find these make the construction a LOT easier. Doable even for my 68 year old eyes and fingers.

    • @Fluffyshotmephotog
      @Fluffyshotmephotog ปีที่แล้ว +2

      I would like to see pictures of your construction. I am going to go outside of my comfort zone and try to build this. I guess no better way to learn than to watch others and be ready to make mistakes. LOL - NØLUV

    • @RandyBuxton
      @RandyBuxton 10 หลายเดือนก่อน

      Works as described. Much easier way to build these things.

  • @porkyfedwell
    @porkyfedwell 3 ปีที่แล้ว +41

    OK, confessional time. I am 61 years old and can see out of one eye. My hands are very, very stable. After working under a high power magnifier I was able to mount the SMD capacitor - no problem. Wound the toroid - no problem! Soldering the primary stub to the center conductor - biiiig problem, but I did it - barely. That's when the trouble began. When I was ready to start adjusting the toroid windings, the primary stub broke free from the center conductor. And then, it did again. Very frustrating! :)
    THEN, it dawned on me: Why are you doing this, Dumdum? Why am I not just mounting the transformer on a postage-stamp sized PC board, and forget about this design? Do I really care if the thing is as small or as slick as Adam's? No! I refer you once again to the fact that I'm 61 years old. 5 years ago this would have been no issue to build, but 5 years makes a big difference. Time to face reality, dude. I'm 61. Not 25, not 51, not 55... 61.
    It then dawned on me that the transformer being on a PC board would make it no larger than one of the traps (which are also built on a PC board). The whole thing will still be exceptionally small and light. This confirmed in my mind that I have made the right decision... for me. I will now have an antenna that's not quite as "cool," but very portable and lightweight. And I will happily continue this project with far less frustration and far more enjoyment.
    Thanks Adam, for this video! It's a great design - for the young. The rest of us will need to engage the gray matter and adapt this to our own diminished capabilities, whatever they may be. Don't laugh at me, it happens to everyone sooner or later. Well OK, maybe I give you permission to laugh a little bit. Chuckle, at least. When I'm not looking. :) lol 73 de KD8ZM

    • @alanshapiro6545
      @alanshapiro6545 3 ปีที่แล้ว +3

      Adam's slick development and presentation of the end fed multiband is great, but for you I would suggest to alter the plan: enclose the toroid and the capacitor in a tiny case, permanently attach a 3-6 ft. length of RG-174 to it going to your transceiver, and finally replace the SMD capacitor with a discrete one. That will give you some space to more easily work with. Also the length of RG-174 will act as a counterpoise which may be beneficial on 40m. I've built my matching device inside a tiny dental floss sample from my dentist. Got that idea from WS0TA/KT5X.

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว +7

      Yes indeed, this is a much simpler method of construction. It's a slightly larger overall package, but for most, that's not going to matter. Unless you're counting grams and measuring in cubic millimeters, it's easy to simplify the design and stick it in a small enclosure.

    • @gblan
      @gblan 3 ปีที่แล้ว +2

      There are plenty of people older than 61 who can do this with ease. Age has nothing to do with it.

    • @Inkling777
      @Inkling777 3 ปีที่แล้ว +10

      @@gblan Age does have something to do with this... just not in everyone.

    • @genepierson1728
      @genepierson1728 2 ปีที่แล้ว +4

      Lets all slow clap for gblan

  • @macgyver5108
    @macgyver5108 3 ปีที่แล้ว +6

    A HUGE "pro tip" for soldering faster and easier is to use additional paste flux/rosin EVEN when using "flux core" solder! It not only cleans up the solder joints better for more solid contacts, but it also conducts HEAT better too, so you don't spend as much time making your connections which saves quite a bit of time too, which seriously helps prevent you from "toasting" heat sensitive components! It's also a good idea to dip your iron tip into the rosin to clean the tip and then brush the tip with a "BRASS" wire brush, not steel which will scratch the "tin" tip on your iron and royally screw it up... Just make sure to blast the rosin off with something like brake/contact cleaner once you're done or else it can make a MESS down the road!

  • @gruvyalan
    @gruvyalan 4 ปีที่แล้ว +17

    You really break this down. Every QRP operator needs to watch your videos...if for no other reason than to learn what makes for resonant, effective antennas!

  • @JarlSeamus
    @JarlSeamus 3 ปีที่แล้ว +1

    As a new HAM but a 35 year Electronics technician, I am very impressed with this design. I could see this as a brilliant commercial product, but also scalable for use in higher output transceivers! Just WOW. 7-3, KD2SML

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว +3

      Thank you Jarl! I initially thought about trying to commercial-ize it, but the construction methods were a bit too finicky for mass-production to be easy. A friend, N7MCB, came up with an improvement on the construction that I'm pursuing that makes it much easier to build. Perhaps I'll at least go down the road of making kits, if not finished products. In the end, I'm most interested in getting others to build, tinker, and have some fun rather than just make a buck.

  • @acestudioscouk-Ace-G0ACE
    @acestudioscouk-Ace-G0ACE 4 ปีที่แล้ว +5

    Thanks for this, good to see an micro alternative to the usual FT240-43 using configuration.

  • @phildurall7466
    @phildurall7466 3 ปีที่แล้ว +2

    Uber impressed with the construction skills Adam! At my age, I don't think I could pull it off. This TRASHES the image of modern Hams as only being appliance operators! Surface mounted components squashed a lot of the fun of building our equipment. This is pure inspiration!

  • @russellwatkinson
    @russellwatkinson 2 ปีที่แล้ว +2

    Great tip for using the spool of wire thanks.

  • @haramanggapuja
    @haramanggapuja 4 ปีที่แล้ว +10

    "Tweezers are huge help." Yeah. So is not having essential tremor. Enjoy your youth, amigo. Steady hands make this kind of project so much easier. Which is why, for me, everything has to be big and ugly and point-to-point thru-hole style. ;-) Nice project.

  • @edmoreno9308
    @edmoreno9308 4 ปีที่แล้ว +10

    Did I mention “You Da Man” again! Thank you from Louisiana. Great project while shut down.

    • @edmoreno9308
      @edmoreno9308 4 ปีที่แล้ว +1

      How did you make your antenna traps? I could barely see in the video.

  • @olafelsberry9271
    @olafelsberry9271 3 ปีที่แล้ว +2

    That's gotta be a fancy beer, looks like I'd drink one or twelve.

  • @psjarvin
    @psjarvin 4 ปีที่แล้ว +6

    You're a wizard. I guess I need one more antenna... At least.

  • @thuff3207
    @thuff3207 4 ปีที่แล้ว +1

    Not a bad idea and it was nice you showed us how you make it!

  • @metaller_alex
    @metaller_alex 3 ปีที่แล้ว +2

    Good craft beer is major essential component for this project I beleive ;))

  • @gmanshackshack6822
    @gmanshackshack6822 4 ปีที่แล้ว +4

    I wish I could still see well enough to make such dainty connections

  • @hamradiotube
    @hamradiotube 4 ปีที่แล้ว +2

    Now that, my friend, is one sexy looking antenna. Nice tip with the spooling of the wire too. Can’t wait to see the finished product!

  • @miketaylor6700
    @miketaylor6700 ปีที่แล้ว +1

    That, my friend, was an amazing video. I’m going to watch the whole series of course… and then… omg.. I may order some supplies. Can I do it??? This scares me as much as my first QSO with CW!!!

  • @ke6mt
    @ke6mt 4 ปีที่แล้ว +8

    Absolutely incredible. This makes for a really great antenna setup for portable ops. I love using it with my MTR-3B. 73, Rex KE6MT

  • @neilisawesome
    @neilisawesome 3 ปีที่แล้ว +1

    So I finally go around to building this and the nanoVNA says that it's pretty awesome, although I haven't yet gotten on the air with it. I did want to point out one funny thing that I learned the hard way. You seemed to laugh about your "fancy BNC connector holder," but I'm pretty sure that it's impossible to do without the vise-grips - I melted two BNC connectors (one pretty obviously and one more subtly in a way that I didn't notice until I tried to connect it to something) until I followed your lead and used the vise grip. I think it's a big fat heat sink!
    Thanks for the build!

    • @porkyfedwell
      @porkyfedwell 3 ปีที่แล้ว +1

      Same here. Sat the connector in 1/8" of water and soldered the other end, after melting two in a row.

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว +1

      Connecting it to a spare female BNC works like a charm! Give it a try.

    • @neilisawesome
      @neilisawesome 3 ปีที่แล้ว +1

      @@K6ARK thanks, Adam. I’ll give that a go next round.

  • @HAMRADIODUDE
    @HAMRADIODUDE 3 ปีที่แล้ว

    I worked my first SOTA with this antenna. It worked GREAT. convenient for rapid deployment. Additionally, the Velcro band around the kite winder and a small tree branch, worked excellent. Thanks again.

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว +1

      Yes, I am looking into having them manufactured, probably without a crystal installed for options. I'll be sure to announce it to the community tab on the channel if/when they become available. Kits aren't really an option with the tiny, tightly spaced components.

  • @malenve6vid
    @malenve6vid 4 ปีที่แล้ว +2

    Finally got around to try and make one, not so easy as the video shows. All of a sudden I feel old trying to construct it.
    Adam, you are the master here. Malen VE6VID

  • @alexwalters1699
    @alexwalters1699 4 ปีที่แล้ว +3

    A great design for an ultra-compact EFHW, along with many great tips. I will be making one for my QRP rig. Thank you!

  • @scottlindquist8628
    @scottlindquist8628 4 ปีที่แล้ว +3

    Absolutely incredible Adam! The ultimate SOTA antenna.

  • @Cardassiaprime
    @Cardassiaprime 3 ปีที่แล้ว +1

    That has to be the most innovative and coolest, Antenna build I have ever seen, I will be building one but not with a surface mount that small.( my soldering aint that good) Thanks for sharing the concept n build. Now I gotta go figure. Barnie M7PBX.

  • @dickwendell7642
    @dickwendell7642 4 ปีที่แล้ว +4

    Brilliant design. We will have to call this the K6ARK antenna. The use of the BNC connetor is the key. The surface mount capacitor creative space saver and the tuning technique simple and effective. I used your BNC technique with a different toroid to complete a similar antenna yesterday. Works great. 2000 mile contacts on 5w and 15w. I only wish I knew about your tuning technique before I epoxied it up. Keep up the great work. It will be interesting to see your traps. Dick K7ULM

    • @kennethbell4681
      @kennethbell4681 4 ปีที่แล้ว +1

      I'm building one from your parts, tonight, Dick. It's taken me long enough to get started!

  • @jasonconrad9212
    @jasonconrad9212 3 ปีที่แล้ว +3

    I just built this antenna, challenging and very rewarding! Thanks for the info!

  • @tadekboruta328
    @tadekboruta328 3 ปีที่แล้ว +1

    Very cool design integrating everything into the connector. Would like to point out though, that the capacitor is only useful for higher frequencies (15m and above). So you can safely skip cutting the BNC.

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว

      Yes indeed, that is true. For 17m and below, the capacitor has negligible effect and is not necessary.

  • @ksb2112
    @ksb2112 3 ปีที่แล้ว

    I have built and used this antenna with some remarkable results. Just this past weekend I was able to hit France and Spain from Southern California using 5 watts. The only thing that seems odd about it is that the received signal strength seems low. I'm getting 559 or higher reports from people who are barely showing up on my S-meter. Admittedly my observation is strictly anecdotal. I need to set up a another antenna to get some direct comparisons going. But dang, France and Spain...

  • @tomon7dc225
    @tomon7dc225 3 ปีที่แล้ว

    Great video, gave me an idea... not so multimate portable. But is used the tip about the windings to make a 40m efhw. Winding and then unwinding. I did the winding-art without the capacitor and could see multiple dip's in the swr. After connecting the capacitor i did a sweep again, and the SWRdips on the other bands than the 40M where lower then without the capacitor.... another lesson learned why i need to use the capacitor. Thanks for the video.

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว

      Yes! The capacitor helps get the resonant multiple higher bands closer to 50 ohms.
      If you find that their point of resonance is a bit off (for example, 20m is usually a bit above the band when 40m is good) try adding a loading coil 1-2 meters from the feed point, and a bit of extra wire to the end of the antenna to get it back into resonance. The loading coil close to the feed (or the end of the wire) provides more inductive loading on the higher bands than it does on 40m and will bring those bands into resonance when the rest of the wire is tuned to 40m. Good stuff!

  • @cwguy8960
    @cwguy8960 4 ปีที่แล้ว +1

    I really like your tuning method. My EFHW toroids all seem to work well, but I wonder how much better I could have optimized the match using your technique. It was one of those "Now why didn't I think of that!" moments...! Thank you!!

  • @timmcdonough8543
    @timmcdonough8543 4 ปีที่แล้ว +3

    Excellent project and very good quality video of the details! Might be a bit tiny for my old eyes but the tips on how you tuned it with the spool of wire was worthwhile all on its own. I'm anxious to see the installment where you build the traps. Tim N9PUZ

    • @jonathanhaynes9950
      @jonathanhaynes9950 ปีที่แล้ว

      As am I. I looked for the traps video to append this one. Is it forthcoming? Still, an excellent video that yielded an antenna here. W0XO

  • @gregmihran8616
    @gregmihran8616 3 ปีที่แล้ว

    Was I the only one getting nervous watching you do that grinding so close to your fingers? Wow Adam, great design and build! You're technique is a pleasure to watch. 73 KJ6ER Silicon Valley

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว +2

      Ha, thanks Greg! FWIW, those diamond blades are abrasive cutters and you can touch your skin lightly with them running and they won't hurt you.

  • @taki8592
    @taki8592 4 ปีที่แล้ว

    DE Z33ST, Hi K6ARK I've constructed efhw antena for 40 meters as you describe on your video with a small variation, i used bnc conector and 10 cm of rg58 the toroid and the capacitor were connected on a small piece of perf board and soldered. Today I had succesfull SOTA activation with my chinese 49 er cw rig, power about 1 watt. Thanks 73 de Z33ST.

  • @dan_nux_vlog
    @dan_nux_vlog 2 ปีที่แล้ว

    Just wondering he came out with brilliant idea... Never thought about it before 👍👍👍👍..... Salute.. 🙏🙏🙏🙏

  • @daviddietrich9449
    @daviddietrich9449 ปีที่แล้ว

    Adam, I applaud your ability to do SMT. I have two Pico Tuners from SOTABeams. I had to ditch the 100 pf SMT cap for a thru hole one. I'm really good at kit building and soldering, but surface mount is just too small to work with for me.

    • @K6ARK
      @K6ARK  ปีที่แล้ว

      Yes, it's a challenge, especially with the smaller 0402 components! Hot air and solder paste help a lot.

    • @daviddietrich9449
      @daviddietrich9449 ปีที่แล้ว

      I will probably have to try it again sometime, but would probably need a good magnifier since my depth perception is a little diminished.

  • @RandyBuxton
    @RandyBuxton 10 หลายเดือนก่อน

    I've constructed a few of these contraptions and have always had to redo after, so it seems, I've put too much epoxy on it. When I tune it (before epoxy) it works as described here. When I put just enough epoxy on the outside (not the sides) of the toroid to hold the wire in place and then re-test it works as described. But when I put epoxy on the sides of and inside the toroid (where the solder joints are) to, conceivably, hold everything solidly in place it where I run into a problem.....testing after this final epoxy application results in the matching unit not resonating on any frequency. As if it has been shorted out.
    So the moral of the story (as far as I'm concerned) is to only put epoxy on the outside of the toroid to just hold the wires in place. Then use liquid electrical tape for the rest of it.
    If someone has come across this problem with epoxy as I have I'd be interested to read how you conquered it.

  • @chuck4050
    @chuck4050 4 ปีที่แล้ว +1

    Very cool build Adam and great camera work 73!

  • @JnJTrueOutdoorAdventures
    @JnJTrueOutdoorAdventures 4 ปีที่แล้ว +2

    Great video Adam!! I guess I will wait now before I build the other antenna until I see this one completed!! Juddie WD8WV

  • @claudem.p.7969
    @claudem.p.7969 4 ปีที่แล้ว +3

    very well explained and got very interested in how you tune the toroid. ty

  • @johnblood4614
    @johnblood4614 4 ปีที่แล้ว +5

    I"d second the request for the supply list for the traps. Looks like more toroids (but which ones??), a small breadboard (where did you source that?) and I'd bet there are some components under the toroid on the breadboard. I'm loving building your antennas. Could you advance a supply list for the traps so I can have everything ordered?? THANKS! Lovely stuff. 73s KD0AXQ

  • @jeffdyer2393
    @jeffdyer2393 4 ปีที่แล้ว +3

    Awesome video. I make a portable efhw I use an empty bic lighter to house the transformer. one end the antenna wire comes out and the other I use about 3 feet of rg174. it works great, small, and looks cool. I'm looking forward to the next video. Keep up the good work.
    Ke4fwe

    • @BretChilcott
      @BretChilcott 2 ปีที่แล้ว +1

      Jeff. Do you have photographs of your design? I would like to see it. TNX Bret C / AC0AE

    • @jonathanhaynes9950
      @jonathanhaynes9950 ปีที่แล้ว

      @@BretChilcott @jeffdyer2393 I, too, would like to see photos of that design.

  • @gilgsn
    @gilgsn 4 ปีที่แล้ว +5

    Tiny! Great design. The smallest I use is FT-82-43. I always laugh when people tell me anything under a dual-FT-240 isn't efficient. Presumably, twisting the three primary turns is better. I am surprised the ground passing through the toroid isn't a problem. I potted one transformer in epoxy; it no longer worked; did it twice, same result, so caution there. Hot glue has no effect...

    • @K6ARK
      @K6ARK  4 ปีที่แล้ว +2

      I was worried about the ground going through the transformer too. I have found that this design requires 9:1 to 10:1 turns ratio typically, so maybe it has some effect in that respect. I'm certain they're not the most POWER efficient matching units around but they are certainly the most SIZE and WEIGHT efficient 😉. Also, incidentally, I have had no issues with the 5 minute epoxy as potting compound.

    • @gilgsn
      @gilgsn 4 ปีที่แล้ว +1

      It might be the reason for 10:1, who knows.. As long as it works.. I use 24 turns total..

    • @K6ARK
      @K6ARK  4 ปีที่แล้ว +2

      Nice. FWIW, I have found that using two primary turns and 18-22 secondary turns also works.

  • @ol2tmx
    @ol2tmx 3 ปีที่แล้ว

    Wow, this is an amazing tiny antenna. I have to test it with my Belka-DX.

  • @thedmutz
    @thedmutz 3 ปีที่แล้ว +1

    Hi folks, maybe this tidbit will help someone if you're getting weird analyzer readings during the tuning steps. In my setup I used a spool of bell wire instead of the wire wrapping wire that Adam uses and readings were coming out very weird on my nanovna. I ended up cutting an approximate length off of the spool and readings immediately looked better. I'm not sure why my wire doesn't work similar to Adam's, but hopefully this may help someone!

  • @CharlesSmith-dh7gf
    @CharlesSmith-dh7gf 2 ปีที่แล้ว

    I wish I could get my hands to work to build one

  • @backcountryamateurradio
    @backcountryamateurradio 3 ปีที่แล้ว

    you are an absolute genius. I love this and can't wait to make one. Thanks for showing us how you do it. you're the man!

  • @christopherbenetatos5123
    @christopherbenetatos5123 ปีที่แล้ว

    Great detail. I learned a lot!

  • @Hookmodo
    @Hookmodo 2 ปีที่แล้ว

    WOW thank you so much for sharing. You are a wizard of HF

  • @DAVIDGREGORYKERR
    @DAVIDGREGORYKERR ปีที่แล้ว

    That end fed antenna might work on the 11Mtr band for those who want it.

  • @prephampaul
    @prephampaul 7 หลายเดือนก่อน

    My next project, Thanks Adam!!

  • @moonchild2213
    @moonchild2213 2 ปีที่แล้ว

    Excellent build...enjoy all your videos, great information.

  • @ernstmattle1155
    @ernstmattle1155 3 ปีที่แล้ว

    Wonderful work from Innsbruck

  • @MiscDotGeek
    @MiscDotGeek 4 ปีที่แล้ว

    Making videos is hard. You did a great job with the video and the build of course. I'll be checking out your other videos as I dive into the EFHW for my own use and on my own blog.

  • @ut4uum462
    @ut4uum462 4 ปีที่แล้ว +1

    Thanks for Your video. Very nice idea to place the toroid on bnc.

  • @KipIngram
    @KipIngram 2 ปีที่แล้ว

    Geez... I can see my next money sink is going to be an antenna analyzer. :-| That little unit you used 3/4 of the way through seems awfully nice.

  • @Inkling777
    @Inkling777 3 ปีที่แล้ว

    As others have noted, some of the fine-motor skills and eyesight required are beyond many. You might want to look around for a young mom wanting a 'from home' job who'd offer your marvelous ideas for compactness full assembled.

  • @w6mrd900
    @w6mrd900 4 ปีที่แล้ว +1

    Fantastic! Thank you for the great video. So much in such a small package.

  • @thejoker-ie1mm
    @thejoker-ie1mm 2 ปีที่แล้ว

    Great idea for SOTA Adam! 👍 Best 72/73 de IK2RGV Steve

  • @KB1HQS
    @KB1HQS 4 ปีที่แล้ว +2

    Thanks for sharing. That is some seriously creative antenna building! Subscribed! 73

  • @randalltom9750
    @randalltom9750 3 ปีที่แล้ว

    Adam... great video... a marvel of miniaturization. I’m into it... QRP kits include the MTR3b (original), and an even older Mountain Topper the dual bander with the Data mode. I follow Gil the ‘Radio Prepper’, and his endeavors towards ultra compact/portable low-draw, survival radios. The Weber designs are amazing rigs.
    I also have a KX2, but the small CW only radios hold my attention.
    72! Hope to see you down the log!
    KD7UXQ. Rand

  • @michaelharriman6080
    @michaelharriman6080 4 ปีที่แล้ว +1

    awesome video adam. When are we getting part 2???

  • @K6TJO
    @K6TJO 3 ปีที่แล้ว +9

    I am having a hard time following what wire ends get soldered where. Do you have a diagram that would show this exactly? Thanks from K6TJO

    • @Wayde-VA3NCA
      @Wayde-VA3NCA 3 ปีที่แล้ว +2

      Hi Adam K6ARK, this is a fun build! I have your version with the tiny, red, round pcb and I'm liking it a lot! I wound that tiny toroid this evening :-) Question about the toroid winding. In the video, you indicate that the twisted stub is the coax center and the short middle stub is ground. I've seen diagrams that indicate the reverse. Have you found that the polarity of the primary matters?

  • @northwesthamshack9950
    @northwesthamshack9950 3 ปีที่แล้ว +1

    Fantastic video, im going to build this ! Thanks for the video

  • @joyhamradio
    @joyhamradio 3 ปีที่แล้ว

    Cool! I’ll definitely repeat this construction!

  • @nathancross405
    @nathancross405 4 ปีที่แล้ว

    Do you have a video describing the traps construction. I'm eagerly awaiting instruction! Thank you so much for showing off your design.

    • @K6ARK
      @K6ARK  4 ปีที่แล้ว +2

      Not quite yet... I've started filming and should have a trap video out some time soon.

  • @M0RSF
    @M0RSF 3 ปีที่แล้ว +1

    Brilliant Adam. This would be an ideal antenna for my QCX mini. I currently use a half wave dipole but your design is obviously smaller and lighter. All the best,
    73 Chris M0RSF

  • @dongelinas5990
    @dongelinas5990 4 ปีที่แล้ว +1

    Wonderful instruction video

  • @MrLuisDeAlmeida
    @MrLuisDeAlmeida 4 ปีที่แล้ว +1

    We'll wait for this kit on ebay .... :-)

  • @glevideo
    @glevideo 3 ปีที่แล้ว +1

    Not sure traps are needed. My 80 meter end fed half wave has resonant points in all bands from 80 through 10 meters ( including 17 and 12 ) without any tuning or traps. Admittedly my EFHW uses a larger transformer for accepting 100 watts of power but it's still 49:1 and the theory should be the same.

  • @javajoe668
    @javajoe668 4 ปีที่แล้ว +1

    Very cool! Thank you for sharing

  • @marcolauritano1777
    @marcolauritano1777 3 ปีที่แล้ว

    Congratulation, thanks for sharing your knowledge.

  • @wkjagt
    @wkjagt 3 หลายเดือนก่อน

    This is really cool! I want to build an antenna for my QMX (which I should receive in the mail this week) and my rockmite, and this video is a big inspiration. I know this is an old video, so you may not even see this question, but where did you get that box of toroids?

    • @K6ARK
      @K6ARK  3 หลายเดือนก่อน +1

      Amidon sells a variety pack that is very useful. I picked up a Plano fishing tackle box with adjustable dividers for storage and organization, then supplemented with additional/other toroids.

  • @LevyCarneiro
    @LevyCarneiro 2 ปีที่แล้ว +1

    Does anyone recommend a good resource (book, site, etc) on how to build this type of antenna for different characteristics? For example, if I want to build one for 40-meter band and takes 100W, what should I change in the materials and turns and dimensions? Thanks.

  • @dongelinas5990
    @dongelinas5990 4 ปีที่แล้ว +2

    I’d love to build one but I have severe sight problems. 😢

  • @ve2evn543
    @ve2evn543 4 ปีที่แล้ว +1

    Great build tutorial. Did you make a separate video for the traps? I can't find it.

  • @aeromech8563
    @aeromech8563 3 ปีที่แล้ว +1

    Subscribed awesome stuff ✌️😎🇦🇺

  • @aaronjohnston1584
    @aaronjohnston1584 2 หลายเดือนก่อน

    Aren't you creating an additional turn or two by passing the antenna lead through the toroid?

  • @michaelfuchs1467
    @michaelfuchs1467 3 ปีที่แล้ว +2

    Great video!
    'Fusing' the toroid to the antenna connector is exactly what I've been thinking about TRYING for a while - but probably using two FT-50-43 toroids stacked, using a 49:1 ratio winding and probably a ~1.5kV capacitor for handling 20W in a multi band EFHW for the G90. I'm 'into' digital EMCOMM so it will be close to 100% duty cycle.
    Have you tried building a 49:1 EFHW this way? 🤔

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว +1

      Yes, I have. Consider a slightly larger toroid. For better power handling, but a couple of stacked 50 size ones should be good at least for 10w.

    • @michaelfuchs1467
      @michaelfuchs1467 3 ปีที่แล้ว +1

      @@K6ARK Thank you for your answer!
      I'm having a hard time finding toroids of right mixture, in right size and for sensible prices here in Scandinavia, at least those made from recognizable material mixtures (43 Nickel-Zinc in this case). I can only find a few Amidon toroids at my local suppliers and also those are being phased out from the stock lists now. I've found a few Ferroxcube as well but not made from 43-equivalent mixtures - and equivalent tables for ferrite materials used by different manufacturers seems non-existent.
      The toroid sizes available here are 240, 140 and 50 if I remember correctly. Of these only the 50-size would make sense mounting the way we're talking about here - in an ultra portable configuration.
      I certainly was hoping for a bit more than 10W with two 50-size toroids stacked, and perhaps a bit thicker wire (~0.75 mm I guess would be possible wound on a 50-size toroid - whatever that is in AWG)...
      Stacking more that two toroids just 'feels' wrong somehow - like as if the physics will be seriously screwed up by the proportions (wire length / turn) . 🤔 I'm definitely on thin ice here and it's probably worth a try since other transformers (like those wound on 'binocular ferries') works well for their intended purposes. Maybe by tweaking the number of turns while keeping the ratio..?
      Do you know of an impedance transformer calculator (unun) that takes ferrite core geometry as parameter in the calculation?
      Do you know if it's possible to wind an impedance transformer using a ferrite rod as core? 🤔 That would make another attractive, slim-line 'package option' - if it's possible. (I can't really wrap my brain around what really happens in the toroid windings compared to what would happen in a non-toroidal core. 🙄
      Regards from Arctic Norway! 🇳🇴 🗻 ☺️

  • @nlo114
    @nlo114 3 ปีที่แล้ว

    Next project: SMA matching transformer?

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว

      I may or may not have already done that 😜. Also, an RCA connector version for the older MTR3B photos.app.goo.gl/T3acBRWeuBs82D3o7

  • @120dale
    @120dale 4 ปีที่แล้ว +4

    I like my homemade dipoles for SOTA but this project may change my thinking!
    Excellent video, thanks.
    AA7OY

    • @120dale
      @120dale 4 ปีที่แล้ว +1

      Found all the parts on eBay to make this.

  • @rfdave3980
    @rfdave3980 3 ปีที่แล้ว +1

    Wound as a auto transformer. Shouldn't the twisted wires go to ground of the BNC, or it doesn't matter?

  • @m6osd217
    @m6osd217 4 ปีที่แล้ว +1

    Awesome. Don't suppose you fancy selling me one to use on 20m band😉

    • @K6ARK
      @K6ARK  4 ปีที่แล้ว +2

      Sorry, I don't sell them at this point. I work far too much to have time to make and sell these as a side hobby.

  • @ThatguyFirst
    @ThatguyFirst 4 ปีที่แล้ว +2

    Is it critical that you have AleSmith on hand, or can you substitute another IPA such as Dogfish Head, Stone, Voodoo Ranger, etc. Also, what about the choice of vessel: aluminum can (conductor) vs. glass bottle (insulator)?

    • @K6ARK
      @K6ARK  4 ปีที่แล้ว +1

      You get at least an extra 3dB out of the antenna if you pour into a frosted glass. 😉 🍻

  • @stickmenwithrayguns
    @stickmenwithrayguns 3 ปีที่แล้ว

    If you change the wiring direction on the toroid the result would be more elegant. ; )

  • @garychap8384
    @garychap8384 2 ปีที่แล้ว

    @7:03 ... and always remember to demagnetise your fingers after working with a coil !
    ; )

  • @LaurentEgliAdventure
    @LaurentEgliAdventure 3 ปีที่แล้ว

    Really nice work!

  • @Ei2iP
    @Ei2iP 4 ปีที่แล้ว +2

    Top guy, great Project Adam, de Ei2iP

  • @BradSnyder1
    @BradSnyder1 4 ปีที่แล้ว +1

    Nice build Adam! 73

  • @tvpartscompany8197
    @tvpartscompany8197 3 ปีที่แล้ว +1

    good job

  • @metaller_alex
    @metaller_alex 3 ปีที่แล้ว +1

    I wonder that epoxy works well on this transformer. I think I saw video of Radio Prepper where he said epoxy affects transformer really badly and he had to give up using epoxy.

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว

      Interesting. I gave not had any issues with performance of these transformers, nor have I noticed and change in tuning after application. I assume the type of epoxy and its contents make a difference. Perhaps his epoxy was a different material.

    • @antennafarmer7380
      @antennafarmer7380 3 ปีที่แล้ว

      I have also heard people saying this. If some types of epoxy cause it and some types don't it's best to just avoid it altogether unless you have different types and are willing to take the time to test them all.

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว +1

      @@antennafarmer7380 since that comment, I have used some other epoxies, and some certainly have a significant impact! Using electronics grade silicone as a potting compound is likely a better option. That's what I have started doing, and it seems to work well.

    • @simonbeliveau6852
      @simonbeliveau6852 3 ปีที่แล้ว

      Epoxy increases capacitance by a factor of 4 compared to air. This is where the observed issues may be coming from. Regardless, i will be using it, silicone has a permittivity of about 2.5, not so different from epoxy. Just dont gum it up too much.

    • @antennafarmer7380
      @antennafarmer7380 3 ปีที่แล้ว

      @@simonbeliveau6852 Eurethane foam has a lower capacitance but you have to be very careful about how much and where you put it because it can light up with high voltage. I used a little in a transformer I've had up to 10W and so far no problems but it's a calculated risk.

  • @robclarke4631
    @robclarke4631 3 ปีที่แล้ว

    Hi Adam, I love the video. Very well shot and well explained. I note you connected the autotransformer shared primary / secondary connection to the primary center conductor. Most EFHW transformer designs I've seen have the shared connection connected to ground. Do you see any benefit to the way you have it connected? It obviously tunes well. Regards Rob.

    • @K6ARK
      @K6ARK  3 ปีที่แล้ว +1

      Thanks. I have actually built them both ways and have not found there to be any notable difference. Perhaps a topic for another video?

  • @Severris
    @Severris 2 ปีที่แล้ว

    Great video, like all your videos. Question...what heat gun is that? I have a compact heat gun about that size, but I really like the nozzle on yours. Thanks.

    • @K6ARK
      @K6ARK  2 ปีที่แล้ว +1

      I have two heat guns. The smaller one is actually a hot air rework station. It's a Chinese model from Amazon but works well. amzn.to/3yL14yi (associate link). Ive had it for about a year and use it for SMD/solder paste board assembly, hot air rework, and shrinking heat shrink tubing.

  • @ljay3030
    @ljay3030 2 ปีที่แล้ว

    Awesome !!

  • @stevek4stb221
    @stevek4stb221 2 ปีที่แล้ว

    Love your videos Adam. Do you have a place to order your portable keyer that I have seen you use? A friend got a prototype somehow and I loved it!

    • @K6ARK
      @K6ARK  2 ปีที่แล้ว

      Steve, send me an email via k6ark.com and I'll get you on the early notification list. I'm building up the first batch now...

  • @vne2328
    @vne2328 3 ปีที่แล้ว

    Nice work~

  • @HikingWithCam
    @HikingWithCam 3 ปีที่แล้ว

    This is great. Thank you. For a 20m version, would you do fewer turns?

  • @michaelharvie3530
    @michaelharvie3530 ปีที่แล้ว

    Hey Adam can you provide a link of where you get those tiny capacitors? I would greatly appreciate it and awesome video. I look forward to building mine soon.

  • @gsansoucie
    @gsansoucie 4 ปีที่แล้ว +2

    Nice video. First thing, wow, that display on the Zoom model, I have the crappy AA-30 base and didn’t realize what I was missing. How much of a difference do you see between your spool out wire near ground trick to an actual antenna suspended from a mast? I’ve always tuned my antennas in their deployed position which takes forever. I like your idea way better.
    I’d seen photos of one of these matching units on the BNC, but could never figure out how it was done as I only use crimp BNC connectors. Guess I’m ordering some solder BNCs now (and I just placed an order a few weeks ago).
    Cool, I was supposed to be building traps for my MTR3b for a 20-30-40 EFHW, but got distracted. That is now tomorrow mornings project.

    • @K6ARK
      @K6ARK  4 ปีที่แล้ว +2

      I rough-tune using the spool with the wire close to the ground, then send out a few extra feet and fine tune in the operating position. Great question, and your approach is the way to go.

    • @KB1HQS
      @KB1HQS 3 ปีที่แล้ว +1

      I have the same AA-30. Use the AntScope software coupled with the AA-30, much easier to tune traps and this antenna.

  • @w7mvg-mike39
    @w7mvg-mike39 หลายเดือนก่อน

    How do you determine what power the matching unit can handle? For instance, if I wanted something to work with my 20W g90 what toroid and wire gauge would I need ? Thx

  • @jessgypin-ko5ds
    @jessgypin-ko5ds 8 หลายเดือนก่อน

    Did you not test the connections before sealing it all up?

    • @K6ARK
      @K6ARK  8 หลายเดือนก่อน +1

      It's probably not a bad idea. Look for continuity between the BNC center pin, ground, and the antenna wire.