EFHW End-Fed Half-Wave Antenna Kit | Part One: BUILD
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- Опубликовано: 4 апр 2022
- Get radio active! In this video, you're guided STEP-BY-STEP by ARRL member Rob Zielfelder, Jr., N1NUG, to build an End-Fed Half-Wave (EFHW) Antenna Kit! The easy-to-build kit is great for new hams (and ALL hams) seeking a simple and effective antenna to get active in the exciting world of HF (shortwave) radio operating. Unlike the dipole antenna, the End-Fed Half-Wave is a half-wavelength antenna with the coaxial cable for your transceiver attached at one end. It has become popular with portable operators because it’s very simple in its construction and deployment. The antenna works on 10, 15, 20, and 40 meters.
For written, step-by-step directions, visit: bit.ly/3MVNRZL or www.arrl.org/end-fed-half-wave...
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To purchase an End-Fed Half-Wave Antenna Kit, visit:
home.arrl.org/action/Store/Pr...
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Special thanks to Rob, N1NUG, for his help with this video! Check out his channel, SevenFortyOne: bit.ly/34R40ye or / sevenfortyone
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I wish this video had been available when I built my kit. I found the instructions on the website hard to follow. This video is much better and has great detail. Well done.
I like the fact you use a star lock washer where the wire connections are. I found through my own experience at work to use a star lock washer.
This is a great how-to video. Thanks for the clear close-up pictures! Thanks also for the description of the stacking order of everything on the bolts -- it took me a while to figure it out from just the pictures in the ARRL instructions and the RFKITS instructions. I think the most difficult thing when I built the kit was trying to wind the wire, especially the doubled primary+secondary coil, tightly around the toroid. Suggestions on that would be welcome.
TIP: Drill the big hole for the SO239 and mark and drill ONE bolt hole. THEN attach the socket with one bolt and use the base of the socket as a template for the other three holes. That way, you don't have to re-drill misplaced holes! 😉
Does anybody know the size of the screws/bolts, washers & nuts used for the SO239 connection?? I'm trying to put something like this together myself sourcing my own parts locally...
Very helpful. I built the kit before this video came out, and the written instructions were not too clear on some points. But with a little thought it came out OK.
Nice looking kit. 👍📻⚡️
Two things I would recommend:
1. It's a bit easier to do the soldering with only the bottom two bolts holding the SO239 in place. It's much easier to see and "get at" the ring connectors without the other hardware in the way.
2. It is possible to install the SO239 "upside down," which won't hurt performance, but it makes it much more difficult to solder the third wire and capacitor in the center of the SO239. Install the SO239 so that there is a bit of a "scoop" in the center post, which will make it much easier to see and solder.
In the original manual for HF kits, they install SO239 into the box but not install outside the box than you, it is more beatiful box. Perhaps is more easy install outside because inside need a more big hole that 16mm to conected a full conector in so239. Nice video, great result and nice data test for all people And it's also the first video I've seen about these kits that use tooth washers well :) , thank you ARRLHQ.
Good job! Thanks.
Rob, I'm stopped partway into a build. A few comments - plus an important question about something that's holding me up. I assume if clarifications are useful, you could just add some online text to the video , like other how-to people do on YT, instead of having to re-edit the video. .
1. I was confused at first by the ring connector insulation removal because there are three of them. Ultimately you remove them all later, but I worried at first because I pulled it from one of the ones with the large hole instead of the small one you started with. An onscreen text clarification might help.
2. I used tape to hold the coax connector against the box at the outside, because it's hard to work it subsequently without screws etc falling off - maybe worth an onscreen suggestion. I also got away with using just one 8 mm wrench instead of two by holding the other side in place by hand.
3 Ring connector at 6:20 - it struck me as odd that its flat part wasn't flush against the box instead of flipped as you seemed to put it on, which makes it deform away from the plastic a bit as the bolt tightens, but maybe there's a reason you did that - maybe an online comment to clarify.
4. Around 8:55 you flip the ring around without announcing that. If you're a noob like me, I just assume I did it wrong and go rewiring it to the right instead, then discover you just flipped it over a second time around maybe 9:23 and I then go rewiring it like it was the first time. An onscreen comment about the flips could be really useful each time you do that (happens again around 9:23).
5. I had to freeze the screen to count the how many times you wrapped it on the opposite side - it could be helpful to put an onscreen text comment there.
*** 6. I followed very closely - paused, stepped forward 5 seconds in places, left or right arrow, for anyone who doesn't know how to use that, and frame by frame using < and > keys can be useful too. But even as carefully as I did this, at 10:15 I seem to have 7 wraps at right as you do but appear to have 4 on the left instead of 5 as you appear to on the screen before the 5cm strip goes outwards underneath (and I had to pull it from under another wrap in consequence of where I started wrapping per the onscreen images. SO the critical question is, does this matter, does that numerical precision materially affect performance in consequence of turn ratios or anything?
7. I don't have flux, I just have solder with a rosin core right now. Will this make a difference, especially since you said contact here was key? Also, will it matter if some of the stripped copper is in contact with the iron ring at all? It might be helpful to clarify for the ignorant.
I'd like to have this ready for Field Day, but it's more important to just not screw it up if some tiny detail like a missed turn will do that.
Hopefully I don't have too many more questions after that. Look forward to your answers - and I appreciate the video, it's far more helpful than the detail-skipping pdf.
Hmmm, my comment is gone. Nice build! I have the MyAntennas EFHW 8010. I like it. I am getting another from a friend once he gets his tower finished. I plan on deploying it 90 degrees to the old one. I am not sure if that will help me TX or RX from different areas? Thoughts?
A little more detail on winding the balun would have been nice.
I agree. I've watched several videos on this particular kit, and all of the windings have looked different to me :)
That's what I wanted to see too. Very poor presentation IMO.
My first winding didn't look so good, so there was enough wire for a second try and it turned out good
I built this ARRL kit, and with the full length wire (78ft), the SWR low point was at 6.3MHz. I shortened the wire 10 feet, and it was perfect for 40m (SWR = 1.2). However, the 20m SWR=4.2, the 15m SWR=5.3, and the 10m SWR=4.6, all too high for my rig. No counterpoise used. Any suggestions on how to make this antenna work on all 4 bands? Thanks.
78 feet??... that length doesn't resonate with anything. Try 64' for a 40 to 10 meter antenna or 130' for a 80meter to 10 meter antenna... for resonance on the lower ends of the band you might put a 5 turn compensation coil about 2meters from the feed point for the 80 meter effort and 1 meter for the 40. Haul at least 1 end up as high as you can.. preferably both ends and your counterpoise is the coax shield..If you use the coax as a counterpoise do not use any chokes on the coax at the antenna feed point... maybe down by the rig...the above antenna length figures are for insulated wire, taking into account the velocity factor.. if you use bare wire the lengths will be greater by 2 or 3 feet. Works great for me.
Excellent video! It really helped! 73
Make sure the when installing the SO239 that the short part of the center wire connector "opening" is facing up to facilitate soldering. If it's facing down, you can't get to the wire and it's impossible to solder.
lol,,I got lucky and installed SO239 facing up,,lol,,I did this before reading your post,,,KI5TFZ,,Thanks for future reference !!
Does anybody know the size of the screws/bolts, washers & nuts used for the SO239 connection?? I'm trying to put something like this together myself sourcing my own parts locally...
Nice
I like your toys for applying flux. I have never seen either of them. I am interested in making an antenna for 160 meters. Have you got a "recipe" for one? Either end fed or some sort of dipole. Thanks.
how many watts?
What about a hole in the box to allow for moisture to drain out?
You're having to drill the holes anyway so I guess you can do that yourself?
I thought about drilling a weep hole on the bottom (the side with the socket) and putting gasket goo around the bolts and putting liquid electrical tape on the back of the socket, but I didn't (yet, anyway). I got the bolts pretty tight. What would you (or others) recommend?
The case comes with an elastomer (?) seal that doesn't quite reach around all 4 sides. If you leave the two ends 1" apart on the bottom, you may accomplish your goal without making an entrance for insects.
How about a good sealing job on the lid and a dehumidifier packet inside taped to the side. If everything else is well sealed there shouldn't be any condensation to deal with.
12 total wraps with 2 in the primary is a 36:1 transformer. Is that what your plan for the EFHW calls for?
It's actually 14 wraps!
The two wraps in the primary are bifilar so there are actually 14 wraps on the Secondary.
Part 2?
Any reason this can't be built for 80 meters with a 134' wire?
No, no reason. That should work. You could also do it with a 110 uH loading coil. So aprox. 66 ft wire than the 110 uH coil and than another 8 ft of wire.
After experimenting with the ARRL kit and the 65' wire, I did exactly that (replaced the 65' wire with a 130' wire) and it works nicely.
@@joeb3300 TNX for the info,,my kit has a sticker that claims the balun work from 3.5 - 30 MHz,,,will keep in mind your experience
Why if we are in the usa we need to use metric i use inches , feet , yard ??
You don't NEED to use metric - the kit comes from England and the instructions are specified in metric. You can convert to imperial measures, or use a metric ruler. As most hams refer to the 40 meter band and the 23 cm band, not to the 131-foot band and 0.75-foot band, we already know metric measures and that seems easier than converting.
Because the kit was clearly designed, and imported from, outside of the US. If the metric hardware sizes don't give it away, note the PA2 call sign on the instructions. At least they do give the equivalents in inches, and I suppose you can use adjustable crescent wrenches. But we all had to learn metric prefixes (2m, 70cm) to pass the exams and get our licenses, right? A few metric tools are probably a good investment.
Because using the metric at drilling the holes makes measurement vastly easier. I tried figuring why a pdf build guide online placed the coax connector off vertical center closer to the connection edge than the outside of the box, and if I'd just centered it on 5 cm midpoint (box is 10cm) and 2 cm short midpoint like in this video, drilling the 5/8" SAE/imperial hole would have been much simpler. And as Joe B suggested, you're building your box for the 20m band, not the 65.5 foot band.
We should have converted to metric back in the 70s when we were educating kids to use it *sigh*. Well, at least the military has enough smarts to use it.
The bands and frequencies are in metric, all modern radios are built using metric, heck, even nearly all U.S. manufacturing uses metric outside of the construction industry. We spend thousands of dollars on this hobby, and can't be bothered to pop a 20 dollar bill for a metric tape measure?
Price of $69 Box should be pre-drilled ready for assembly - Keep It ARRL
And the SO239 connectors should have been installed as well for that price.
Oh and the torroid wrapped and everything soldered and while they are at it seal the case too?
Hello!!! It’s a kit with all the parts provided. A nice quick build.
@@BenWorrell Hello. its an overpriced rip off ; )
I built this yesterday. There are several errors and omissions in this video. I recommend the assembly video from the “Ape”.
Good video, Rob -
Minor correction: It's not "Metric" and "English", it's "Metric" and "Imperial". We'll let a Connecticut yankee get away with it - this time ; )
lol
We down under switched to metric many years ago and it is so much simplier than Imperial.
Just in case you don't have a step drill, they are about $40 (or so) at big box stores
Or $5.99 at Harbor Freight. Or $12 at Amazon. As you are only cutting through soft plastic, the quality of the drill bit is of less concern. I would not spend $55 on a Milwaukee.
"Any project that requires the acquisition of new tools is thereby a good one."😀
I found the point where you wrap the wire very confusing. You keep on flipping over the Torrid and your hands are always in the way to show what you did. I had to repeated stop the video, watch it again to figure out why my wires don't agree with you (cause you flipped), and reorient the torrid before continuing.
Absolutely confusing! No mention of the number of wraps once you crossed over the toroid, hands in the way, reversed viewing orientation. Also the position/orientation of the holes in the plastic box do NOT agree with the printed instructions/pictures on the ARRL website! Thanks but you or the designer needs to review and correct.
I REQUEST that you add "inches" to all videos for us older Hams that refuse to convert to metric. This is so tiresome to have to figure out the conversions.
Poor, hi Z antenna. Why not just build a proper dipole? Cheaper, perfectly tunable unlike this hi Z kluge
Because this antenna, with a ~130' antenna wire, works on 80M, 40M, 20M, 15M and 10M w/o an antenna tuner. It also only requires two support points - my house and a distant tree.
But this gets multiple bands without all of the work of tuning all of the branches of a fan or parallel dipole (which is what I've been using the last couple of years).
Because It is Multiband, It works well, Its smaller than a "proper" Dipole, and it is easier to install. Did I mention it works.
Not sealing the penetrations you are making so the gasket for the top is pointless.🤡
"Metric to English"? How about Metric to Imperial. 🙄