K6ARK Matching Unit Kit Build - End-Fed Half Wave (EFHW)

[@45auto]

I'm going to need Professor Farnsworth's glasses to see that capacitor. 😀

[@nathansharp9957]

Definitely will not need the finglonger to grab it though

[@ChrisN8PEM]

Just finished my EFHF Build. Total finished length 61.5'. Flat 1:1 SWR across 40, 20, 15 and a good chunk of 10. No Coax - direct to radio. My tip: I placed a loop of paracord thru the small loading coil and use that as my lash point on the radio end.... the 6' of wire between that and the BNC are then 'loose' for connection to the radio. Thanks Adam!

[@mattghoward]

nice - like the use of the board mount connectors - I built the original version grinding away the connector :-)

[@motorvids]

Everybody should buy and make one of these. Adam's channel has been a great inspiration to me. He is a great teacher and very innovative. I have made several items based on his videos and been very successful in the QRP arena. Amateur radio operators need to support people in our hobby like Adam. Thanks for this video and I just placed my order. Well done! KJ7PRS

[@owlcricker-k7ulm]

Glad te see your ME skills and creative juices flowing. 72 OM

[@rfdave3980]

Wow Adam your engineering is showing, fantastic design. Nice idea using the PCB and BNC PCB mount. 73

[@PortableRadio]

I built and tested a bunch of different EFHW couplers and yours ticks all the boxes for minimalistic QRP in outdoors. Your previous KZbin video, in which you built the 1:81 transformer was really innovative, that's why I linked to it in my EFHW document. This kit makes it even easier to built this kind of versatile antenna and still allows to play with different radiator designs. Well done!

[@harpmatt100]

I BUILT up mine this afternoon. Wonderful. It really works. Endx halfwave antennas are great. I have experiences with Fuchs antennas. You only need a short counter poise ore even none. That's the advantage of these kind of antennas. I like that antennas.

[@nvrumi]

Very well done design improvement, Adam. This will make the build a lot easier than the old kits. You're an excellent teacher, Adam. Your explanations are very clear. 73 de AG7TX

[@ianmcqueen13]

Wow! So much easier than doing it from scratch. Following your previous video, it took at least 4 tries before I go a working model. But the pride!

[@TheTechPrepper]

Very well done, Adam. What a beautiful DiY kit and project. Keep up the good work!

[@michaelharriman6080]

I ordered before even starting the video. Built the original version for 20m and gave it to a friend for their QCX. Will build this one for 17m for my QCXmini. Congrats on the kit release. I’ve missed your videos.

[@gliderrider]

Ok I got one. Hot dang, it works! I screwed up and tried to save money buying Chinese wire instead of ‘wireman’ silky wire. So I tuned it to be droopy so as not to stress out the cheap wire. Still works! Added a piece of 20’ coax. Still good on 20 and 40 meters. This is great!

[@michaelmcghie]

Thanks Adam for the well put together video. Being new to building an antenna, this will help for my first. 📡

[@K6ARK]

Please follow the written directions as the build process has been modified a bit. The updated toroid winding method is a little easier and the boards were updated to accommodate for additional build options.

[@nickrupp2336]

Thanks ! As soon as I seen this video I went straight to Amazon and ordered 2 of your kits.

[@K6ARK]

Awesome, Nick! Please feel free to reach out to me with questions or if you have any issues. I want to make sure everyone is successful in their builds.

[@nickrupp2336]

@@K6ARK would it be possible to make this be able to handle 20-25 watts by using a bit bigger wire ?

[@K6ARK]

Wire is not the limiting factor, the toroid is. You can add a FT82-43 toroid and nest the FT50-43 in the center, then wind it as if it is a single toroid. Works great for up to about 30-35 watts!

[@nickrupp2336]

@@K6ARK thank you!

[@K6ARK]

@@nickrupp2336 built that way, it's a fantastic G90 antenna. I may make some G90 kits at some point... 🤔

[@obiter-things]

Hi Adam, great kit and great video. I recommend one additional step before soldering the BNC: Do a continuity test to check that the enamel has actually burned off. Desoldering and resoldering the toroid after the BNC is in place is a real bear-I learned the hard way, 😂

[@SarahC2]

I notice he trimmed to the surface of the PCB, so when he soldered - the end of the enabled copper is exposed to the solder in case the enamel doesn't burn off.

[@K6ARK]

@SarahC2 a hot iron is key. Mine is set at 825 F right now. It also helps to use a mid-sized to larger tip.

[@SarahC2]

@@K6ARK My JBC should manage that, thanks for the temp.

[@mattghoward]

Just built this version - sooooo much easier lol thanks - goes well with my qrp field kit

[@daniell8387]

I can't wait to put mine together after work today! Funny I had most of the components except the board and the BNC Connector

[@martinhuyett7502]

I built the 9:1 version today. Messed up the toroid winding! But found 3 colors of same sized wire and wound 3 separate windings. Colors made connecting them easy. With 29 ft element and 17 ft counterpoise tuned nicely and had 3 POTA hunter QSOs on 40, 30 and 20 at 5 watts CW. Got good reports. Thanks for good kit!

[@mountainwalk1169]

Just ordered. So excited

[@craigsharples6324]

Awesome kit, will be ordering a couple shortly!

[@vaamorais]

Hi There! Greetings from UK. Great video and really happy to learn you came up with a way to make your design available to purchase. First time I saw you build one I said to myself I will struggle with the tiny capacitor directly to the BNC. This KIT makes everything easier. Thanks.

[@johnsinclair3067]

Just got mine. Great kit. Be careful when bending the posts on the female connector. They snap if you fiddle with them too much.

[@K6ARK]

Yes, they do. If you damage more than one lug, let me know and I'll get you a new BNC and updated PCB that fits better. Or, if you just want the PCB before building the kit so you don't have to bend them, I'll be happy to send one. All future kits will have the updated PCB specifically designed to fit the female BNC rather than the generic male one.

[@johnsinclair3067]

@@K6ARK thank you the offer. I am good - just wanted the first gen folks to know to go gently :)

[@jeremytanzer279]

I've got a couple on the way. Can't wait to have my own K6ARK antenna!

[@DK5ONV]

Happy New Year into San Diego County... 💯🎸🙋‍♂

[@SarahC2]

Cool! Thanks for the video. The webpage instructions have in/gnd/out for the wrapping of the toroid which would have led to a cross over of the enamelled wire into the PCB I have. Following these instructions 10:55 I've got in/gnd/out, the right order for the little black PCB I've got!

[@K6ARK]

Follow the written instructions. The board has been updated from when this video was made.

[@SarahC2]

@@K6ARK Ok, I will. Thanks!... looks like it's working great! I used a bit of blu-tak to steady the PCB for soldering the capacitor. =)

[@moistmoustache420]

Just bought one of these bad boys .. super keen to give it a go

[@robertpastorella]

Are you planning another round of these? Or maybe the a PCB on OSHpark? I would really like to build one of these

[@SarahC2]

They're selling again.

[@haroldskinner1783]

Adam would love to see a short video on wrapping the 9:1, i have read your instructions over several times, but would still love to see it done, being from Missouri, Show me 😊

[@acestudioscouk-Ace-G0ACE]

An excellent video, lots to learn and good tips even if you don't buy the antenna, which you should.

[@Pabloisradical]

My kits in the mail, can’t wait to get it

[@tortellini-doodles]

Excited to build this today, thank you!

[@ChrisN8PEM]

He's Back! It's been too long Adam! I just placed my order. Been waiting for this or a long time. Instructions look great!

[@K6ARK]

Thank you, Chris, and thanks for the Christmas letter and bookmarks. What a brilliant idea. I love it. Sometimes life gets busy and it's hard to keep up on video production and editing, but I'm definitely still around and creating. That won't stop any time soon even if it is a bit less frequent.

[@ChrisN8PEM]

@@K6ARK No problem! Thank you so much for putting these kits together. I can't imagine the work involved to get to this point. Hoping with this kit to 'lose the coax' in the future lol.

[@Medic-ui9ms]

Just ordered a kit, looks like a nice little winter project. Thanks for the video! 73, NJ0Q

[@averageguysradio]

Nicely done Adam, IMHO this is one of your best build videos. I built a version of this antenna based on your previous vidios and couldn't be happier with it. It bagged me my first SOTA DX in to Guadalajara Mexico. Keep up the great work/content Adam. 73

[@bubbleheadft]

I've got my kit and I'm hoping to pair it with an FX4C sometime in the future for an ultra-portable rig.

[@JnJTrueOutdoorAdventures]

Thank you for providing the kit! I just ordered one! I never got around to buying the components myself to try and build it back when you had your video of how to build them. So glad you put this kit together. Juddie - WD8WV

[@m.p.6330]

I have 2 that just arrived. Thanks for making these available. I can't want to build them.

[@randalltom9750]

He’s alive! I had thought you’d fell off a mountain, or you were on an extended ‘on location’ action film shoot, doubling for Bruce Willis as a stunt double. Huh, I’m rarely wrong…. But hey, I did build your kit, and hey, I love it… a 9:1 Unun with linked 20-40m legs… Bravo Adam! Now I need to figure out how to install your cap key kit into my QCX Mini…. de W7UDT Rand (dit dit)

[@K6ARK]

Thanks Rand! Yes, I get busy with life sometimes as well, but I do need to get back to making some more videos again. I also need to finish my reply to your email. I do have more cap touch key PCBs and can get another headed your way. Thanks and 73.

[@randalltom9750]

@@K6ARK Hey Adam! Here’s a heads up… I’m working on a protective laced Kydex S/POTA board for my KX2… (what the ‘he double toothpicks’ is that?) My KX2 has rails, so the top molded half of the shell will be clear, and act as a cover for the KX2, being laced together with paracord to the bottom half, a 8x12” flat clipboard… the sides of the top case will be open on both ends, extending an inch or so off each end. The top cover will accomodate the front paddle. It’ll all hang from a lanyard off my neck, so when seated, I can comfortably operate and log my contacts… whatcha think? The laced board will provide the weather and impact protection the KX2 lacks…. Being laced by paracord, it will hold the radio securely.

[@vincei4252]

Happy New Year, Adam. All the best with the kit!

[@K6ARK]

Thank you, Vince, I hope builders love it and are successful with their builds.

[@SteveYancey]

I’ve built a few small ones but I always liked your original build so I ordered a kit. Im looking forward to using it.

[@kodyeliason1389]

Finally! Love the videos! Just ordered two!

[@K6ARK]

Thank you, Kody! Please reach out if you have any questions during the build. 🤘😁

[@GigaBrand]

Whoo just ordered one last night!

[@wild-radio7373]

Fantastic! Ima tell everyone in my club about these♡ although, a few of them already probably ordered theirs! Really appreciate your work!😎👍

[@K4MJV]

I just placed my order. I hope my fat fingers can get in there to build this antenna :)

[@Bill-HRT]

Awesome! I'm building a bunch so I don't worry about losing the one (because I really like your design) I built from your video months ago.

[@dwDragon88]

Nice kit, mine is on the way. I might suggest putting in one or two extra spare capacitors. Those SMD caps are about 10-12 cents purchased in 100 quantity or greater. People are definitely going to lose the cap, burn it with the soldering iron, etc during installation, and it would be a bummer to ruin the whole kit over that one part. I say this completely acknowledging that you've made it as easy as possible with the nice little custom PCB. Nice work.

[@K6ARK]

Good call, maybe worth it. I am also happy to send a spare (they're so small they fit in a regular mailing envelope) if someone damages or loses the one in the kit. Just reach out to me and I'll be happy to help.

[@nickrupp2336]

@@K6ARK could you just use a standard cap soldered to the pads ?

[@K6ARK]

Probably. It would be a tight fit, but I bet it would work. Just make sure it's at least 1kv at 100pf.

[@agplay2290]

Ordered it yesterday.

[@HamRadioDuo]

Adam, any change you have a contact who buys your kits and assembles them and sells them assembled?

[@RadioRunner]

I've said it before and I'll say it again, strongest, most handsome beard in the radio game.

[@RevGunn-jq3cq]

Nicely done!

[@ErnestGWilsonII]

Thank you for posting this video and sharing it with all of us! A few questions please: 1. Is there a place we can buy a fully assembled unit? 2. Do you have a variation where you have built SO239 instead of BNC? 3. Which specific wire would you use if you were building an 80 meter EFHW? That wire is long and I'm wondering if folks have a preferred wire that doesn't tangle and is easy to manage? 4. if you were going to have a multiband EFHW, would you use a 9:1 and a random wire? Or a 49:1 or 64:1 and a half wave wire? When going multiband with 80 m as the lowest band, which of those would be the better choice? Thanks in advance and I am of course subscribed with notifications turned on and thumbs up! 73 W3GUY

[@ON4RW]

Thanks Adam well done !

[@gliderrider]

Now for that micro pixie. Or better, a micro cricket. It’s got side tone! No pressure hihi

[@gregh3248]

Excellent Presentation. Thank you.

[@raithjames860]

Look back on amazon USA and was going to buy a male bnc kit there. Looks like you are out of stock already. I will wait for the next batch. Great kit, excellent videos. I'm learning a ton and starting to build. Thanks

[@K6ARK]

Just sold out! Next batch is already en-route to Amazon. Soon!

[@okhamradio]

Thanks for sharing this information

[@kq6up]

You have to sell your Pixy in an Altoid Mini. That thing was awesome.

[@Mottersmotters]

Happy New year Adam to you and you're family. Great video. Motters M7TRS 73 👍🏻

[@boomerbits2297]

just built the EFRW now to test it! de ke4d your valley center acquaintance. back in the day before your time!

[@bruceweight7319]

Wonderful little unit. I would suggest having a blank piece of round pcb same size as the main pcb with a notch for the wires and add it right at the end of the heat shrink process as a cap on the unit and maybe hot glue it to seal it.

[@K6ARK]

Oh, good idea. I may have to test that out. Thanks for the idea.

[@bruceweight7319]

@@K6ARK So fun to see such a light cool unit; a round piece of hard plastic would work too. I could build one for my QCX and it would make a really light small portable unit. I am curious if it was you that I saw tuning one of these types of units using a spool of wire to roll it out while it is connected to the VNA and watch the dips and find the best length. Was that You? they first strung it out and found out how many turns on the coil was best and then trimmed the length of the wire to the best swr. I couldn't remember what the procedure exactly was and have been looking for the video and can't find it.

[@K6ARK]

Nice! Thanks. That is indeed my tuning strategy. I can't remember if it's in a video or if I just described it. Regardless, it works well!

[@bruceweight7319]

@@K6ARK Thanks for the reply. If you get bored maybe do a video on tuning the core and then the antenna sometime. I am sure you get bored haha. Thanks. I am going to look up one of your units on Amazon. Looks like a great unit. I love building stuff and that includes kits. The tuning method could also be used on higher powered antenna's.

[@johnsinclair3067]

WOW!!!

[@NorthCountryHam]

Very nice, I don't normally QRP, but I want to build this just to have one.

[@K5YVY]

Awesome build Adam.

[@willian.direction6740]

HNY everyone. Thanks Adam for sharing and making your design available for everyone who wants to have a go at making an antenna. Hope to hear some dx cool waves from summits in 2022 as bands pick up. Regards Ian vk5cz ..

[@frankalvernas6628]

Awesome! I enjoy your videos very much, especially the antenna build ones. keep up the great work and more videos coming...73 de N6LPV

[@w2msa]

Looking forward to this build. Thanks Adam! de W2MSA

[@K6ARK]

Sweet! If you bought a kit recently, be sure to use the written instructions on www.k6ark.com. they are a little different now.

[@w2msa]

Will do. Should be a nice match with my KX2.

[@AA0Z]

Showing the easy build process will hopefully encourage some more builds. It's a lot less challenging when you show vs tell.

[@87balexander]

Is the low power rating the reason you can get away without a counterpoise?

[@PaumanokSupplyCo]

What size heat shrink for the 26 gauge poly stealth? I want an extra roll laying around for additional links and banana clips. Thanks!

[@503Nick]

I’m looking forward to using this. Should be delivered next week. Slightly concerned with the build and my old eyes 😅

[@W6IWN_Radio]

I want one, EPIC!!!

[@shanebaker9975]

Hey Adam, great video! Curious if you have a recommendation for a multimeter? I don't have one yet and seem to run into more and more uses for one. There are a ton out there and $ to $$$. Thanks!

[@ON3STG]

Hi Adam, impressed by the size and simplicity of the design. Even for me it seems to be feasible to build the kit. Unfortunately it seems to be sold out. Do you have an idea by when this will become available again (in Europe)? 73 ON3STG Gert

[@KD9ZHF]

Is there a calculator online for how many times you need to wrap the toroid with X-type of wire to get a X:1 unun for XXXw?

[@hdcd1]

Nice work! Mine delivers today. Looking forward to the build. Any other antenna builds on the horizon? Thanks.

[@spencerhochstetler]

Hi Adam - thank you so much for your channel which is full of great information! Do you have any plans to "recharge" Amazon (or any other outlet) with these little kits? Thanks!

[@K6ARK]

Yes, I restock as often as I'm able. I am sending another batch of QRP kits tomorrow but they'll sell out fast. Sorry for the delays - the antenna kits are not my day job and my family, regular work, and SAR volunteer work takes priority. Lately, they have been consuming almost all of my free time. Thanks for your patience, and check back on Amazon over the next few days if you're looking for a QRP kit. More 100w kits after I get back from Dayton...

[@68thBC]

Just found this video and I am a complete noob on antennae. Could something like this be built for 10m, 6m, and 2m use?

[@ambitiouslawn1678]

Awesome man!

[@raithjames860]

I see they are back in stock. I just bought two as a way of saying thanks for all your help. I going to build some from scratch as well. Were do you source your antenna winders? Appreciate your work.

[@nicholasmarinelli4575]

I’m about to built this kit. I don’t anticipate using a counter poise but what is the downside of putting it there just in case I want to try it out?

[@K6ARK]

There's nothing wrong with that at all. You can always just cut off the stub if you never use it. Be sure to follow the written instructions. They are a little different than the board that I was using in the video.

[@wolfwizard406]

I only have one hand, any chance this will be available already completed?..

[@chrisbjohannsen]

@K6ARK Portable Radio i bought a kit after watching the HRCC build stream, looking forward to putting it together. I was looking for any info on tuning for EFHW build, I don't see any specific titles, can you point me in the right direction?

[@K6ARK]

Your best bet right now is to review the text instructions. It briefly describes multiple ways to finish the antenna. If you have specific questions after that, fire me an email at [e-mail]

[@aristotleallen5577]

Very cool little kit. Any chance you are planning on making a similar kit for traps?

[@nehem11e]

So hypothetically speaking if someone were building this matching unit and their three year old walked off with the magnet wire and that someone searched the entire house for it but couldn't find it, what would you recommend as a replacement, would any magnet wire work, specific gauge, enamel type, etc? Thanks for any info, it would be helpful if this hypothetical situation were to happen. You mentioned Remington industries in your live stream with HRCC, but they have quite the assortment.

[@K6ARK]

Send me an email, I'll get some sent to you on Monday. No biggie... If you have some laying around the house, any 28 ga or 26 ga magnet wire will do.

[@nehem11e]

@@K6ARK Awesome thanks! Will do I also noticed that the affiliate links in this video description show as unavailable but there is a kit with your name on it with the female connector available on amazon is that just a new link of your or a copy cat. I will send the links I have found in the email

[@K6ARK]

@@nehem11e yeah, it's a long story, but basically Amazon let someone else hijack my original listings because I didn't have a registered "brand". I had to create new ones.

[@nehem11e]

Received the magnet wire. Thank you!!

[@ouijim]

Nice Kit. Looks like Type 43 toroid which worked well for me with 49:1 transformer EFHW. Type 2 (Red) toroid was better for me as I got better performance with 9:1 UnUn, specifically 10m and 6m on NET Nights which I do portable at times ; ) Anyway a must have in my portable setup . How much power will it handle? Thank You. . . Mostly I use T200 Type 2 (RED Toroid) 9:1 UnUn, Type 43 RF Choke, 29ft wire and 17ft counterpoise (EARCHI Antenna)

[@K6ARK]

Yes, it's a -43 mix which works well in all 3 build options. I generally recommend a maximum of 10 watts for lighter duty-cycle modes and 5 watts for modes like FT8.

[@washingtonstatepicker3460]

Thank you

[@JhKnife-OZ4HJ-Jimmi]

Hi Adam. Cool kit and nice video. Pleas make that tuning video. I have no problem building these things, but the tuning is always different than what I see on KZbin. #73 - OZ4HJ

[@washingtonstatepicker3460]

Is the second video up?

[@larspregge6420]

Nice kit.

[@keith-ww5g668]

Hey Adam, when do you think the antenna kits will be back in stock on Amazon? Bought the male BNC kit, but want to try the female BNC kit and add a counterpoise. Great Kit!

[@K6ARK]

Thanks! I should have more in stock within a week on Amazon. 😁👍

[@robertaldrich2635]

I just built the EFHW version with female BNC, ready to tune the wire but don't see your video you mentioned (to tune the antenna length) at the last of this one. I guess I can experiment, someone below said 61 feet but I'll start with 68 or so. I did test it out (using the internal tuner and about 50 feet of wire) and got a weak signal report on 7.255 with my G90 on five watts. What is the max power recommended with the EFHW?

[@K6ARK]

Start with a bit more than half a wavelength on the desired frequency of operation and fold back the end of trim to resonance using an analyzer, or trim to minimize SWR if you don't have an analyzer. The standard build is good for 5w on heavy duty cycle modes and 10w of lighter duty cycle like typical SSB.

[@craigpalmer9196]

idea not as small and just an idea a double binding post for the base might you get two antennas?

[@K6ARK]

You can build a similar antenna out of a BNC to Binding Post connector. Chuck, KK6USY had a great video about this build. It's about 4x the size of this (but still pretty small in the grand scheme of things) and easy to build.

[@K6ARK]

Chuck's video... kzbin.info/www/bejne/eJKzfqiEjL57irs

[@iracG5]

i world love to use that new winder you show last in that livestream, please share it whit us:)

[@K6ARK]

Yes! I've been building up some stock and will have them available soon.

[@iracG5]

@@K6ARK please Share the .stl file i got myself a 3d Printer

[@raithjames860]

I have seen these kits on Amazon usa. They are awesome. Any chance of getting them on the Canadian site? The shipping is just as much as the kit to get them up here.

[@K6ARK]

Rob, I'll take a look tonight to see what it would take for me to do this. I'm new to Amazon selling, and have been fumbling my way through it. Let me see what it takes to get this set up. Thanks for your patience.

[@gregorybarra5376]

Great video, kit ordered! I'll be building an efhw, any guidance on the loading coil? I looked for another video and didn't find one.

[@K6ARK]

As described in the build instructions, adding a 10-12 turn coil at 5-6 feet from the feed point helps bring the SWR dips for the resonant multiples of the half wave frequency into the desired spots. I really need to do an EFHW tuning video one of these days.

[@gregorybarra5376]

@@K6ARK Thanks! Kit's not here yet, so no build instructions, lol. I figured I was learning as much by video as I could prior to arrival. Looking forward to it!

[@K6ARK]

@@gregorybarra5376 no problem! Build instructions are at www.k6ark.com

[@gregorybarra5376]

@@K6ARK Got it, thank you! 👍👍👍😎

[@matutep1]

Hi Adam!!! What antenna wire is recommended for the 5w, 20w and for the 100w kit?

[@K6ARK]

My favorite portable antenna wire is Poly Stealth. I like 26 ga for the smaller kits, and although 26 ga will also work with 100w, I like 22 ga for the nicer handling characteristics.

[@matutep1]

Thanks for the info!! ​@K6ARK

[@Aimsport-video]

Great stuff. Hypothetical question ;) For R&D of windings for any higher power product… have you seen DL2MANs recent video for capacitorless winding and will you include that in your experiments? Thank you for doing such great things for the portable operations Ham community!

[@K6ARK]

Yes, but there are better ways to test as well. Check out AI6XG's blog.

[@charleszimmermann7784]

Does it hurt to add the counter pose, even if you are not intending to use it?

[@Wayde-VA3NCA]

Hi Adam, I have one of your early pcb kits and have noticed no continuity between counterpoise pad and coax sheild pads, is that because this is an isolated transformer design rather than autotransformer? Intentional? (Btw ,a really fun kit!! Thanks! )

[@K6ARK]

Wayde, good find! That was an error with one of the earilier versions of the boards. Please send me an email and I'll be happy to get you one of the latest kits to build.