Would anyone be interested in an End-Fed Random Wire Antenna kit? It would probably consist of the toroid, wire, SO-239, and maybe a box if I can find one at the right price point. Leave a comment if that would interest you.
I would love to see more videos like this. Also, some U-Tubers do not cover all the details which makes it frustrating for new Ham's. Thank you for a fantastic video with all the details!!!
Finally some logical explanation on long wires. So many videos and text on the internet about long wires yet they're all in the same self fulfilling format (lemons) with little thought for those of us starting out into HF. We need the baby steps of A to Z which is exactly what you've done here, and without a silly Ernest Hemingway beard! Subscribed.
Thanks for airing our QSO! A good 9 to 1 and random wire is tough to beat in terms of band hopping speed with a decent tuner. I sent over some pics of how I mount my FT-140-43 toroid into paracord winders with a SO-239 for POTA. Winds out and up quick onto the spool/winders to maximize on air time! 73 and thanks for the contact. KD2YAR Joe
Thankyou so much. I'd Like commend you on serval points. 1. Clearly you know you subject matter very well. 2. Your presentation is clear, focused and to the point. I see so many videos that meander and ramble off into irrelevant diatribes. I learned a lot from you in this little video, thank you again, and please keep up the good work!
Excellent. Works great. First contact with this balun fed with 75 ohm coax & connected to a non-resonant random wire 15 feet above ground w/ a short vertical counter poise was 875 miles on 15 meters with 25 watts SSB.
Great video, thank you! I use a 107 ft non-resonant end fed, 9:1 unun. The trick for me was a very long counterpoise (didn't measure, but longer than the antenna, turns twice to fit space). Works great to talk on 160 thru 6 meters with tuner in the rig!
I was successfully able to make a contact on 2 meter with 73 feet of wire attached to the ferrite diagramed in your video. I soldered the 6 ends into a breadboard, soldered and shrink wrapped the wires and cable.. I did end up moving the antenna to a different spot and ultimately found that the counterpoise worked best right under the antenna by someodd feet. Because I could bot run out the entire 73 feet in a straight line I wrapped it around a 10 foot long structure that was about 6 feet high. I found I was only able to use medium level power on my tyt9800 but it could have been my computer sitting next to the receiver was interfering with it when I was maxing it out. Or maybe just going back into the line. At any rate, I am going to test the antenna woth a nano tomorrow. Thanks again. And 73.
I often run basically the same antenna as described in the video for POTA activations. Operating QRP less than 5 watts, I have several thousand QSO's with it using a 41 foot wire, about 20 foot counterpoise, to the XMFR and manual tuner. It works particularly well on 40,30, and 20 meters. Even worked a fair amount of DX during activations... Paul NA9M
Thank you Mike for this great video, I have been looking for a good DIY video on how to construct a 9:1 unun, this was surely easy to follow your procedures on the unun's construction.
I'm still relatively new to HF and I live in an HOA and have found that an EFHW is perfect for my shack right now. They're easy to put up and take down (mine isn't weatherized yet) so it works for me. Thanks for the video Michael. 73! Michael-WA5AZQ
I've literally just put up a 9.1 end fed as I wanted to use 40m. I have a small garden but it works really well. Noise floor is s3 on 40m. Been put off for years using wire but they really work! Great video 73
In 1979 I worked the world with TenTec Century 21, my 93' random wire and MFJ tuner as KA9EDP, I wish back then my Elmer had a lead on these cool variations! Looking at some of my potential POTA options though I will also have to include compact verticals in my mix to be flexible for site requirements. I enjoy visiting many of the local sites as we full-time RV even if I don't have a modern portable rig yet. Cheers, Dave, KU9L
Awesome video as always Michael. This is going to sound weird, but I hope you don’t stop putting your into into your videos. Out of all of RUclips, your intro is the only one I don’t skip. 73
Just to follow up a bit on Michael's video - there are actually quite a few non-resonant antennas that will actually outperform their resonant cousins. The problem is that many people restrict their choice of feedline to just coax. Using balanced line opens up an entirely new set of possibilities for antennas - many with both lower loss and gain as compared to say, a resonant dipole (the extended double Zepp is just one example). Many such antennas make excellent multi-band antennas as well. Balanced line also is actually less prone to producing RF in the shack (as compared to coax) as long as the antenna itself is a balanced load.
Parallel feed line can be a game changer and opens up a whole new world of multi band antennas. It isn't without its challenges, though. I do have some open feed videos planned.
Hey Michael, great video you did a beautiful job of winding the transformer and put it together in that box. Really impressed by the antenna. Thanks for the video and take care. WD5ENH Steve
Thanks and vert timely. I have two EFRW 9:1 antennas now. Tomorrow, I'll be putting up one of them in the attic as I live in a condo townhouse and that's the only place it can go and one of the few configurations that will work in my space. Not ideal but best available option. In fact, in one of your livestreams a year or so ago, I asked about attic antennas and you and your guest at the time gave valuable advice. I've chosen a 41ft radiator with a Nelson 9:1 matching box and 17ft counterpoise in 18awg wire. For POTA, I've been using a TufteIn 9:1 antenna, also 41ft/17ft with light 26awg wire. Truly portable. Both have worked really well outdoors when I tested them and I'm able to match them on 80 all the way to the 6 metre band. I might try and wind my own toroids net time as your video shows how easy that is to do. 73!
Thanks a lot for you video. I have deployed several random length antennas. I live in a condo in Barcelona. Before I got the permits to deploy a mast, I started with a 22m long wire disguissed in between the air condition machines. It worked quite well considering the situation. Now I have a 5 band wire dipole from Diamond. I have also deployed a RW EndFed antenna with 36 m of wire plus a 9:1 UNUN. It works without tuner in 40, 20, 15 and 10 m. I need to use the tuner for 80m and WARC bands. I would say, it is a esasy to deploy and very versatile antenna, although it is not the best efficient one. I'm very happy with the results. 73's EB3CJR
Great video, got to help deploy one like this at our club FD a number of years back. I built a similar 9:1 and have been using it successfully on 160, and lower bands till the recent hurricane Hellene here in NC. Had to pull down our mast for after storm tree work, and the tree guys seem to have got my post jammed, and not been able to extend it back up. Currently building a second one with a shorter line for some of the higher bands. My counterpoise is about 50’, and has a 4’ ground rod on the end.
Thanks for this video. Very informative. I'm working this winter with an EARCHI EFRW in a reverse sloper config (matchbox about 20 feet high, end of antenna about 6 feet high). The EARCHI uses the coaxial braid of the feed line as a counterpoise - have a ferrite core on the feed line where it enters the shack as a common choke. 30 foot wire antenna. With external tuner, I can tune under 1.5 SWR on 40 through 10. It's performed surprisingly well for making contacts! If the snow & rain ever stop here, I may try a different 9:1 matchbox set up for a counterpoise separate from the feed line - you've motivated me to try that.
Nicely done, Michael. Your 9:1 transformer build is excellent and easily understandable. This would make an excellent Field Day Antenna system. Aloha de Russ (KH6JRM).
Hello, I have exactly such an antenna as the only one because I live in a dense urban development and I am very happy with it. The core used is FT240-43, a winding wire with a diameter of 2mm. the length of the beam is 30m. I am very happy with it. best regards, SP2NW 73!
I used a random wire (Packtenna 9:1) with my K2 for Field Day this year. The radiator was only 31’ long and worked great on 20 and 40 meters. To my surprise, my built in tuner in the K2 tuned it to an SWR of 1.2:1 on 80 meters and I made a lot of late night contacts. Hard to beat. Larry - W7LDT
Thank you for the video. I've been curious about end-fed antennas and your video explained quite a bit for me. I don't have space or HOA issues (IE exactly why I moved last year). My entire goal here at the new QTH is to avoid antennas that could be considered a compromise. So I've been putting up full size antennas (even for 160). However, I always love the art of making antennas and this is a good tool to have in the tool belt. 73 Mike KF9UG
Good video Michael I have wound several 49:1 transformer and I getting ready to wind a 9:1 and a 1:1 common mode choke so I definitely like these types of videos. 73 KV5P
Hi, First time here so interesting to see other peoples experiences, I run a 9:1 unun with 84ft of wire in a sloper config, 40m thru 10m are all under 1:1.5 and it seems to work very well, thanks for the vid. Resonant end fed 1/2 wave is typically 2400 ohms at the end hence 49:1 transformation.
I don't believe that there is a prescribed counterpoise length for a non-resonant antenna. Especially when the counterpoise is laying on the ground. I usually use something in the neighborhood of 25-30 feet.
Excellent video with thorough explanations...The tutorial on making the unun is a nice plus! I regularly use an 84-foot with a 9:1 when operating portable. Inverted vee, inverted L, sloper...it's really a good all-around antenna which, despite its compromises, will work just fine for doing a POTA activation, EMCOMM work or anything else in the field. Time to try it at the QTH now!
For my last few POTA camping adventures, when I put up a wire antenna, it's been the end fed random wire. I really like, with a tuner, the ability to go anywhere.
Very nice video. I just installed an EFRW @ 137' long in an inverted V configuration. Works very good on 80-10m on my FT DX 3000 with the internal tuner with average SWR of less than 1.2 on all bands. Contacs to Japan, Chile, Argentina, Puerto Rico, Canada and Brazil from my QTH IN Parks AZ. KK7IUJ Harry
I have used this antenna on 6 meter FT8 with decent results. It does have a bit of an unpredictable radiation pattern on that band, but otherwise works. I haven't been able to get a good enough match with my tuner to use it on 160 meters, though. I think the antenna is too short for that band.
This is a great antenna, I have made them with FT240-43 and FT82-43, as well as the EARCHI design using the T130-2. Both work well, but the ferrite cores work better below 20M. Palomar uses 62 mix in their popular models. It’s better on the higher bands, even 6M. Using a choke at the rig end of the coax is highly recommended.
Just bought my First HF radio. Now looking into antennas!!! Leaning towards building a EFHW because I’m not paying $160-$200 for name brand stuff at Radio shops online.
I love your video. It explains in detail how to do this random wire build and setup. For me, this is great. I don't have a lot of money to spend on antennas. Thank you very much. Do you know if random wire length will affect reception and transmission? Will a 74 ft random wire perform better than a 41 ft random wire? Thank you again. 73 Matt KF4KSK.
Outstanding video. I am getting back into Amateur Radio after a long time due my military travels and would like to go with your idea. How can I order a kit? Thank you.
Hi great video, I built this type of antenna a while ago as I live in an apartment, with 52 feet of thin wire and a 9-1 anun, it works very well but it does not like a counterpoise, but I've added an RF choke of 25 feet of coax, ( 25 feet of the coax cable was wound into the choke as it was quite a long run which I didn't want to cut it,)
Thanks for the awesome video. I would like to see an impedance (or swr) graph without the 9:1 connected and how should the trimming be done to optimally align the measured impedances before connecting the 9:1. I’m using 42ft of thin insulated wire both for the radiating element and the counterpoise. Measured impedances are lower than 50ohm on 20m and above so I’m not using a 9:1. However, my ATU struggles to tune on some bands. Antena elements connected directly to the ATU-100. I’d like to know how to optimize my build. Should I start cutting in hope that impedance go up and use a 9:1? Thank you!
The length of coax matters to a degree as you will have to contend with feed line losses if it is too long. For the random wire antenna I'm using in my backyard, I have 75 feet of RG-8X coax. I'd probably switch to a lower loss coax if I had to go much longer than that.
Thank you for explanation. I going to use your method to mine situation. I have to gutters one slightly longer than other. 80m is very bad, CB is very good. I want to try to make 80m good.
Very informative video. After having been QRT for more than 30 years I wish to get on the air again. Unfortunately I have now very restricted space and a very small garden. My attic is about 9 metres long. Can you fold a random wire antenna?
KI4Z" Use a butane lighter to strip enamel.. some practice to get the time/heat right, but burn it black, then wet or dry 400 sandpaper dipped in alcohol to remove the black ash. Avoid going red hot on the copper. Buff it clean, and tin it.
Thanks for good information. My shack is located in the second floor well above the ground. Can I have the counterpoise just hanging vertically down from the 9:1 transformer?
The thing that holds me back is fear of lightning strikes coming in the antenna and causing a fire. Maybe you have done a video on how to prevent that. I would really want to see how to protect from lightning strikes the right way.
After the snow melts and we can get into our backyards, Joe and I will be talking about lightning protection and how we get our coax cables into the house.
I'm looking into this sort of antenna for portable emergency comms work, so very happy to see you cover it so well! A question, though... around the 3:20 part where you're talking about the desired wire lengths, you say not to use a length that is 1/4 or 1/2 wave resonant multiple on any desired band. I thought it was just multiples of 1/2 wave that you needed to avoid. Can you clarify that because if 1/4 wave multiples must be avoided then my calculations are way off!!!! 73 de BJ, KM4RB
Common mode currents can be an issue with non resonant antennas. I did not put a choke near the feed point as I have a good counterpoise that seems to be doing its job. I do have a choke near the transmitter, though. That's to help reduce man made noise that plagues my residential environment.
Hi great video 1 question whay everybodi is using plastic boxe 4 transformers of end fed or random wier antenas ? I use a 9to 1 cupled wit a adition 9 turns gives me 16 to1 i have a end feed antenna about 217 feet that is about 60 m of wier give or take 5 m ists about 5 meters from the atic flore and about 16-18 meters diference from actual ground.
Does running a straight wire antenna that is not straight cause issues? The one I bought from a another ham said he had troubles because he had a small yard and made a couple of turns like a U. I was told that was 107 feet long.
Can I feed my coax line from my attic to my basement through the same hole as I have a Cat6 cable for my security cameras without interference? Do I have to go through the trouble of drilling new ones?
I'd like to know how you set up your RigExpert to work the way you showed in the video. It scanned the entire band and you have the bands you use highlighted so you only focus on them. Please do a video on that.
It's called the Multi-SWR function. Not all of their meters have it, but for the ones that do, it's a really handy feature in checking multi-band antennas. I'll have to so a quick video on it.
@KB9VBRAntennas Very new to Ham radio. Got my Tech ticket last month. I thought this antenna, or an inverted V, might be a good "first" antenna 📡 for me to get started on 10-meters then other bands once I get my General ticket. Do you use any sort of lightning 🌩 arrestor/grounding with this antenna where this feedline comes into your house? Any advice would be greatly appreciated. 73s Tom KF0 OGU
In the 15:17 mark of this video you stated that we could put up a 10-40M antenna for as little space as 33 feet of space. Does that mean the wire would be 33ft in total for the 40 meters or will it be the normal 66ft for 40 meters?
There are two styles of end fed antennas, end fed half wave and end fed non resonant. The random wire antenna in this video is the non resonant type. So you need a length of wire that is not resonant on any of the bands you wish to use. The 66 foot length would be resonant on the 40m band so it would be considered an end fed half wave. You can use it on the fundamental and the harmonics, usually without a tuner. The wire as short as 22 feet is considered an end fed non resonant antenna. You can use it, with a tuner, on 40m and bands above it. Without getting too deep into the weeds, a non-resonant antenna typically has a lower impedance than end fed half waves, so even in using a tuner, you still receive a high level of efficiency as compared to an true end fed half wave.
So I have a 22.5m wire with a 3.5mm bannan plug on the end of it connected directly to the center of the coax connector on my ft817nd. It seems to receive volmet and ft8 from all over the show. No tuner. Is the tuner only needed when transmitting ? Or will it improve rx too?
Very informative video! For my @home random wire antenna @20 ft of height in inverted L-configuration, I use 84 ft with a 9:1 UNUN. About 30 ft of RG-8X coax runs into the home (shield used as a counterpoise). Near the connection to my multi-switch (for multirigs) a rf choke. Works well on 80-6 meters. I can even couple one of my rigs to the random wire antenna on 160 m, but it is horribly inefficient (haven't made any QSOs yet). I plan to try a 22 meters (71.5 ft) random wire with a 9:1 UNUN for a portable Hamops. Thanks & 73 de AE5ZX
How do you determine the length of the counter pose wire, 25 feet long. Does it matter much if it is longer or shorter? Could an insulated counter pose wire be buried 2 or 3 inches below the sod? Is a ground rod connected to the counter pose side of the 9:1 unun? I’m thinking about trying a 74 foot end fed with a 9:1 unun, running the wire along the bottom roof tiles on my roof. I’m not sure how the end fed antenna will work when it’s in close proximity to my roofing tiles. I’m not sure how much electrical noise the end fed antennas will receive. I’ve heard that they receive more electrical noise than resonant dipoles. I assume it’s less electrical noise received with an end fed antenna than a vertically polarized antenna.
Great as usual. Thanks. I have a ground rod and ground distribution block right where the antenna would hit the house. Is a ground better or worse than a counterpoise? Thanks.
And earth ground and a counterpoise are two different things. The ground will provide a bit of lightning protection, but isn't a substitute for a counterpoise as the RF conductivity is not very strong.
I cannot understand why those making videos on wire antenna seem to never discuss wire length adjustments due to the velocity factor of insulated cable.
Velocity factor for an insulated wire, like the 14ga stranded that I used in the video, is 4%. I believe I mentioned in the video that I don't calculate to velocity factor but instead will trim that 4% when I test and tune the antenna. That gives me a little extra wire to play with when installing an antenna.
Hi My 130 foot, 80-10(my antennas), 49-1 efhw works great. I made and hooked up multiple counterpoises to the ground rod, making 80 work very well and 160, yes 160 work decently! But, My antennas sells a 173 and a 202 foot efhw with a 9-1. Would the extra length improve my bands? Especially 80 n 160?
Adding more wire can increase the bandwidth of an end fed random wire antenna. But for 160 meters, you run into a problem past 202 feet as there aren't any good lengths that will match all frequencies udel.edu/~mm/ham/randomWire/. But, if the purpose of the antenna was only for the 80 and 160 meter bands, you could do the wire lengths calculations specific for those bands and ignore the higher ones. That would give you a wealth of compatible non resonant wire lengths. While you are at it, pick a toroid with the best low band performance and maybe stack two or three together for better saturation resistance.
Thanku Would you say then, to stay w my 49/1 at 130 feet, since its working well, or go to a 9/1 random length at 173 or 202 feet? Will I loose efficiency on the higher bands vs my 49/1? Llastly, with my 49/1, can I solder additional length wire onto the existing 130 feet, and if so, how much would you suggest? Thanks much William
Very helpful and detailed. I wish, however, more was passed along about configuration and length of counterpoise. There’s a lot of confusion on this subject. Some say 1/4 wavelength on lowest band…others borrow the .05 wavelength from EFHW antennas. It’s confusing.
I think it gets confusing because a lot of people overthink counterpoises. I've found that almost any non-resonant length of wire works fine. If it's laying on the ground, the length isn't going to matter a whole lot.
Can the same Magnet copper wire that you are using in this video be used if I had the FT240-43 instead of the FT140-43 that you are using in this video?
Yes it can. The FT-240 will have a higher permeability so you can run it at higher power levels. The 18ga wire will be sufficient for 100 watts, but if you want to do more, or use it 100 watts digital, I'd switch to a heavier magnet wire, like 14ga.
I don't think there are any hard and fast rules, what I would works best is a counterpoise that is roughly half the length of your non resonant radiator.
Of the three antennas, the dipole will have the best performance as it doesn't rely on a matching transformer. As for efficiency between an EFHW and a non-resonant antenna, I think they are pretty equal. You may get slightly better efficiency using a resonant piece of wire, but the losses in a 49:1 transformer will be greater than in a 9:1 transformer, so their overall efficiency is about equal. I wouldn't let someone tell you that an antenna is inefficient stop you from trying one out.
For receive only a non-resonant, or random, length of wire works great. The more wire the better, but something 29 feet or longer will do fine for almost all of the shortwave bands. A transformer isn't necessary.
Nice video, Michael! I love the compactness of the random wire. Unfortunately, it really necessitates a tuner and I do not have one. Maybe I'll build a 40m-10m RW and see what I can get away without a tuner. U-rah-rah.
The sections are welded together. I would try to use it as a receiving antenna only. Would I need a 9:1 unun? To where the center connector should be connected? How about the ground?
I own a 43' vertical which is great for 40-10m, but just so-so on 80, and not-so-good on 160m. So I just ordered an EFHW 80-10m from MFJ. But I really want to get on 160m, so I ordered all the parts for a 9:1 unun.... & I will experiment with a long wire vs the efhw from MFJ. I have 1.5 acre lot with lots of oaks in the 40-45' height range, but the trees are so dense it's a challenge to string a 40' high wire thru them... Doug, K5DHL
I'd love to hear what you find out. I love oak trees because they always seem to have a limb at the right height for hanging wire, but they are also dense and scraggy and tough to get wire through.
Very good presentation. I am interested in this antenna, I do activate a few parks and stay at campgrounds for several days. This antenna will work on the POTA bands and I can check in on the 80 meter nets in the evening without having an antenna running half way through the campground! 73 KI5IMV.
Where can I find “600” ohm ladder wire ? I’ve looked at Home Depot , MFJ , and MTC and still nothing . Closest I find is 300 . Can I Double it to create 600 ? Errr
300 and 450 Ohm window line is pretty common, but the 600 Ohm ladder line can be more difficult to source. Back in the day, most hams made their own with homebrew wood or plastic spacers and 18 ga wire. I did find a source online if you want to purchase some: www.trueladderline.com/w7fg-design-600-ohm-open-wire-feedline/
EARCHI- emergency amateur radio club of Hawaii sells them with correct length of wire for about $50 already assembled I use a fiberglass pole, 32 ft , from Jackite, $75. I use it as a vertical antenna. Add coax and your good to go.
Would anyone be interested in an End-Fed Random Wire Antenna kit? It would probably consist of the toroid, wire, SO-239, and maybe a box if I can find one at the right price point. Leave a comment if that would interest you.
Would buy your random wire kit without hesitation
Yes. Yes I am interested.
That would be good. If it could come with a multi core upgrade option for higher wattages, that would be even better.
Yes. I would certainly purchase one. Let us know when they hit the website.
I am interested.
I would love to see more videos like this. Also, some U-Tubers do not cover all the details which makes it frustrating for new Ham's. Thank you for a fantastic video with all the details!!!
Tnanks, I'm glad you enjoyed it. I also included some good resources in the video description if you wish to explore this antenna more.
Finally some logical explanation on long wires. So many videos and text on the internet about long wires yet they're all in the same self fulfilling format (lemons) with little thought for those of us starting out into HF. We need the baby steps of A to Z which is exactly what you've done here, and without a silly Ernest Hemingway beard! Subscribed.
A lot of videos regurgitate the same content without a thought of research or planning. I'm glad to hear you enjoyed this one.
Thanks for airing our QSO! A good 9 to 1 and random wire is tough to beat in terms of band hopping speed with a decent tuner. I sent over some pics of how I mount my FT-140-43 toroid into paracord winders with a SO-239 for POTA. Winds out and up quick onto the spool/winders to maximize on air time! 73 and thanks for the contact. KD2YAR Joe
Thankyou so much. I'd Like commend you on serval points. 1. Clearly you know you subject matter very well. 2. Your presentation is clear, focused and to the point. I see so many videos that meander and ramble off into irrelevant diatribes. I learned a lot from you in this little video, thank you again, and please keep up the good work!
Excellent. Works great. First contact with this balun fed with 75 ohm coax & connected to a non-resonant random wire 15 feet above ground w/ a short vertical counter poise was 875 miles on 15 meters with 25 watts SSB.
Watched Walter-staton discuss and make 9:1 Unun for long wire. Found yours and learned some more. Interesting how to construct and diploy.
Thanks
Great video, thank you! I use a 107 ft non-resonant end fed, 9:1 unun. The trick for me was a very long counterpoise (didn't measure, but longer than the antenna, turns twice to fit space). Works great to talk on 160 thru 6 meters with tuner in the rig!
Watched this twice and bookmarked. GREAT STUFF....
Best ever description and help with end fed random wire use. Many thanks.
While I bought my own end fed 9:1 Torrid/matching unit then added antenna wire I can confirm that they work very well.
I was successfully able to make a contact on 2 meter with 73 feet of wire attached to the ferrite diagramed in your video. I soldered the 6 ends into a breadboard, soldered and shrink wrapped the wires and cable.. I did end up moving the antenna to a different spot and ultimately found that the counterpoise worked best right under the antenna by someodd feet. Because I could bot run out the entire 73 feet in a straight line I wrapped it around a 10 foot long structure that was about 6 feet high. I found I was only able to use medium level power on my tyt9800 but it could have been my computer sitting next to the receiver was interfering with it when I was maxing it out. Or maybe just going back into the line. At any rate, I am going to test the antenna woth a nano tomorrow. Thanks again. And 73.
I often run basically the same antenna as described in the video for POTA activations. Operating QRP less than 5 watts, I have several thousand QSO's with it using a 41 foot wire, about 20 foot counterpoise, to the XMFR and manual tuner. It works particularly well on 40,30, and 20 meters. Even worked a fair amount of DX during activations... Paul NA9M
Thank you Mike for this great video, I have been looking for a good DIY video on how to construct a 9:1 unun, this was surely easy to follow your procedures on the unun's construction.
I'm still relatively new to HF and I live in an HOA and have found that an EFHW is perfect for my shack right now. They're easy to put up and take down (mine isn't weatherized yet) so it works for me.
Thanks for the video Michael.
73!
Michael-WA5AZQ
Very very clear and instructive video, thanks. Now I have an clear idea of what these antennas really are.
Thanks.
Now we can all build our own end fed antennas! Great video! 73!
I've literally just put up a 9.1 end fed as I wanted to use 40m. I have a small garden but it works really well. Noise floor is s3 on 40m. Been put off for years using wire but they really work! Great video 73
In 1979 I worked the world with TenTec Century 21, my 93' random wire and MFJ tuner as KA9EDP, I wish back then my Elmer had a lead on these cool variations! Looking at some of my potential POTA options though I will also have to include compact verticals in my mix to be flexible for site requirements. I enjoy visiting many of the local sites as we full-time RV even if I don't have a modern portable rig yet. Cheers, Dave, KU9L
I bought the stuff to do this and am making one this afternoon. Thanks for posting the project.
Awesome video as always Michael. This is going to sound weird, but I hope you don’t stop putting your into into your videos. Out of all of RUclips, your intro is the only one I don’t skip. 73
Thank you for the great video! I'm going to give this a try sometime this winter. :)
I like how clean the box looks.
Just to follow up a bit on Michael's video - there are actually quite a few non-resonant antennas that will actually outperform their resonant cousins. The problem is that many people restrict their choice of feedline to just coax. Using balanced line opens up an entirely new set of possibilities for antennas - many with both lower loss and gain as compared to say, a resonant dipole (the extended double Zepp is just one example). Many such antennas make excellent multi-band antennas as well. Balanced line also is actually less prone to producing RF in the shack (as compared to coax) as long as the antenna itself is a balanced load.
Parallel feed line can be a game changer and opens up a whole new world of multi band antennas. It isn't without its challenges, though. I do have some open feed videos planned.
Hey Michael, great video you did a beautiful job of winding the transformer and put it together in that box. Really impressed by the antenna. Thanks for the video and take care.
WD5ENH
Steve
Thanks and vert timely. I have two EFRW 9:1 antennas now. Tomorrow, I'll be putting up one of them in the attic as I live in a condo townhouse and that's the only place it can go and one of the few configurations that will work in my space. Not ideal but best available option. In fact, in one of your livestreams a year or so ago, I asked about attic antennas and you and your guest at the time gave valuable advice. I've chosen a 41ft radiator with a Nelson 9:1 matching box and 17ft counterpoise in 18awg wire. For POTA, I've been using a TufteIn 9:1 antenna, also 41ft/17ft with light 26awg wire. Truly portable. Both have worked really well outdoors when I tested them and I'm able to match them on 80 all the way to the 6 metre band. I might try and wind my own toroids net time as your video shows how easy that is to do. 73!
Thanks a lot for you video. I have deployed several random length antennas. I live in a condo in Barcelona. Before I got the permits to deploy a mast, I started with a 22m long wire disguissed in between the air condition machines. It worked quite well considering the situation. Now I have a 5 band wire dipole from Diamond. I have also deployed a RW EndFed antenna with 36 m of wire plus a 9:1 UNUN. It works without tuner in 40, 20, 15 and 10 m. I need to use the tuner for 80m and WARC bands. I would say, it is a esasy to deploy and very versatile antenna, although it is not the best efficient one. I'm very happy with the results. 73's EB3CJR
Enjoyed the history behind this antenna. Definitely going to do some more research on this!
Great video, got to help deploy one like this at our club FD a number of years back. I built a similar 9:1 and have been using it successfully on 160, and lower bands till the recent hurricane Hellene here in NC. Had to pull down our mast for after storm tree work, and the tree guys seem to have got my post jammed, and not been able to extend it back up. Currently building a second one with a shorter line for some of the higher bands. My counterpoise is about 50’, and has a 4’ ground rod on the end.
Thanks for this video. Very informative. I'm working this winter with an EARCHI EFRW in a reverse sloper config (matchbox about 20 feet high, end of antenna about 6 feet high). The EARCHI uses the coaxial braid of the feed line as a counterpoise - have a ferrite core on the feed line where it enters the shack as a common choke. 30 foot wire antenna. With external tuner, I can tune under 1.5 SWR on 40 through 10. It's performed surprisingly well for making contacts! If the snow & rain ever stop here, I may try a different 9:1 matchbox set up for a counterpoise separate from the feed line - you've motivated me to try that.
New to building antennas. I can see why the seasoned hams say build your own it makes you a better more efficient operator.
Nicely done, Michael. Your 9:1 transformer build is excellent and easily understandable. This would make an excellent Field Day Antenna system. Aloha de Russ (KH6JRM).
Hello, I have exactly such an antenna as the only one because I live in a dense urban development and I am very happy with it.
The core used is FT240-43, a winding wire with a diameter of 2mm.
the length of the beam is 30m.
I am very happy with it.
best regards, SP2NW 73!
Inspiring, I'm off to B&Q (DIY) in the morning, need to get one of these antenna's up in my small garden.
Great video, awesomely helpful
Legit I loved this video!
I used a random wire (Packtenna 9:1) with my K2 for Field Day this year. The radiator was only 31’ long and worked great on 20 and 40 meters. To my surprise, my built in tuner in the K2 tuned it to an SWR of 1.2:1 on 80 meters and I made a lot of late night contacts. Hard to beat. Larry - W7LDT
Thank you for the video. I've been curious about end-fed antennas and your video explained quite a bit for me. I don't have space or HOA issues (IE exactly why I moved last year). My entire goal here at the new QTH is to avoid antennas that could be considered a compromise. So I've been putting up full size antennas (even for 160). However, I always love the art of making antennas and this is a good tool to have in the tool belt. 73 Mike KF9UG
Thanks!
My project for the week!!! 73, N9BRO
Thank you so much for your support.
It's great video. Random wire antenna is good for different situations.
Good video Michael I have wound several 49:1 transformer and I getting ready to wind a 9:1 and a 1:1 common mode choke so I definitely like these types of videos. 73 KV5P
Thanks for the info, excellent video.
Hi, First time here so interesting to see other peoples experiences, I run a 9:1 unun with 84ft of wire in a sloper config, 40m thru 10m are all under 1:1.5 and it seems to work very well, thanks for the vid. Resonant end fed 1/2 wave is typically 2400 ohms at the end hence 49:1 transformation.
Random wire antennas are IMHO, good for base and mobile uses. Cheap and easy to build, as well as easy to deploy.
How long does the counterpoise need to be?
I don't believe that there is a prescribed counterpoise length for a non-resonant antenna. Especially when the counterpoise is laying on the ground. I usually use something in the neighborhood of 25-30 feet.
Excellent video with thorough explanations...The tutorial on making the unun is a nice plus! I regularly use an 84-foot with a 9:1 when operating portable. Inverted vee, inverted L, sloper...it's really a good all-around antenna which, despite its compromises, will work just fine for doing a POTA activation, EMCOMM work or anything else in the field. Time to try it at the QTH now!
For my last few POTA camping adventures, when I put up a wire antenna, it's been the end fed random wire. I really like, with a tuner, the ability to go anywhere.
By adding one more winding you ll end up about 12mhz centered and improve swr in the lower bands
Very nice video. I just installed an EFRW @ 137' long in an inverted V configuration. Works very good on 80-10m on my FT DX 3000 with the internal tuner with average SWR of less than 1.2 on all bands. Contacs to Japan, Chile, Argentina, Puerto Rico, Canada and Brazil from my QTH IN Parks AZ.
KK7IUJ Harry
Have you tried this up up on 6 meters, or as low as 160 ?
I have used this antenna on 6 meter FT8 with decent results. It does have a bit of an unpredictable radiation pattern on that band, but otherwise works. I haven't been able to get a good enough match with my tuner to use it on 160 meters, though. I think the antenna is too short for that band.
This is a great antenna, I have made them with FT240-43 and FT82-43, as well as the EARCHI design using the T130-2. Both work well, but the ferrite cores work better below 20M. Palomar uses 62 mix in their popular models. It’s better on the higher bands, even 6M. Using a choke at the rig end of the coax is highly recommended.
Another great tutorial!
I wrap my cores with 2 layers pf teflon plumbing sealer tape. Thus far, its working fine.
Just bought my First HF radio. Now looking into antennas!!! Leaning towards building a EFHW because I’m not paying $160-$200 for name brand stuff at Radio shops online.
Go for it! Building your own antenna is fun and rewarding.
I love your video. It explains in detail how to do this random wire build and setup. For me, this is great. I don't have a lot of money to spend on antennas. Thank you very much. Do you know if random wire length will affect reception and transmission? Will a 74 ft random wire perform better than a 41 ft random wire? Thank you again. 73 Matt KF4KSK.
Outstanding video. I am getting back into Amateur Radio after a long time due my military travels and would like to go with your idea. How can I order a kit? Thank you.
Hi great video, I built this type of antenna a while ago as I live in an apartment, with 52 feet of thin wire and a 9-1 anun, it works very well but it does not like a counterpoise, but I've added an RF choke of 25 feet of coax, ( 25 feet of the coax cable was wound into the choke as it was quite a long run which I didn't want to cut it,)
What about reactance? Does it get close to zero ohms? Thanks!
I've got some space at home. would like to try 148 ft to see how it will work at 160 m cw portion. but how to pick correct counterpoise length?
Thanks for the awesome video. I would like to see an impedance (or swr) graph without the 9:1 connected and how should the trimming be done to optimally align the measured impedances before connecting the 9:1. I’m using 42ft of thin insulated wire both for the radiating element and the counterpoise. Measured impedances are lower than 50ohm on 20m and above so I’m not using a 9:1. However, my ATU struggles to tune on some bands. Antena elements connected directly to the ATU-100. I’d like to know how to optimize my build. Should I start cutting in hope that impedance go up and use a 9:1? Thank you!
Looking forward to picking supplies and building something new for my limited lot. Does it matter lengths for coax from tuner??
The length of coax matters to a degree as you will have to contend with feed line losses if it is too long. For the random wire antenna I'm using in my backyard, I have 75 feet of RG-8X coax. I'd probably switch to a lower loss coax if I had to go much longer than that.
Thank you for the video. Question, would you ground the coax (lightning arrestor) before it entered the house?
Thank you for explanation. I going to use your method to mine situation. I have to gutters one slightly longer than other. 80m is very bad, CB is very good. I want to try to make 80m good.
Very informative video. After having been QRT for more than 30 years I wish to get on the air again. Unfortunately I have now very restricted space and a very small garden. My attic is about 9 metres long. Can you fold a random wire antenna?
KI4Z" Use a butane lighter to strip enamel.. some practice to get the time/heat right, but burn it black, then wet or dry 400 sandpaper dipped in alcohol to remove the black ash. Avoid going red hot on the copper. Buff it clean, and tin it.
Thanks for good information. My shack is located in the second floor well above the ground. Can I have the counterpoise just hanging vertically down from the 9:1 transformer?
Yes you can. The counterpoise doesn't have to be on the ground, it can be elevated, or drooping downward as in your case.
The thing that holds me back is fear of lightning strikes coming in the antenna and causing a fire.
Maybe you have done a video on how to prevent that. I would really want to see how to protect from lightning strikes the right way.
After the snow melts and we can get into our backyards, Joe and I will be talking about lightning protection and how we get our coax cables into the house.
I'm looking into this sort of antenna for portable emergency comms work, so very happy to see you cover it so well! A question, though... around the 3:20 part where you're talking about the desired wire lengths, you say not to use a length that is 1/4 or 1/2 wave resonant multiple on any desired band. I thought it was just multiples of 1/2 wave that you needed to avoid. Can you clarify that because if 1/4 wave multiples must be avoided then my calculations are way off!!!! 73 de BJ, KM4RB
Did you use a choke or balun on the antenna feed line to capture any RF traveling on the outside of the coax before it gets into your shack?
Common mode currents can be an issue with non resonant antennas. I did not put a choke near the feed point as I have a good counterpoise that seems to be doing its job. I do have a choke near the transmitter, though. That's to help reduce man made noise that plagues my residential environment.
Hi great video 1 question whay everybodi is using plastic boxe 4 transformers of end fed or random wier antenas ? I use a 9to 1 cupled wit a adition 9 turns gives me 16 to1 i have a end feed antenna about 217 feet that is about 60 m of wier give or take 5 m ists about 5 meters from the atic flore and about 16-18 meters diference from actual ground.
Does running a straight wire antenna that is not straight cause issues? The one I bought from a another ham said he had troubles because he had a small yard and made a couple of turns like a U. I was told that was 107 feet long.
Can I feed my coax line from my attic to my basement through the same hole as I have a Cat6 cable for my security cameras without interference? Do I have to go through the trouble of drilling new ones?
I'd like to know how you set up your RigExpert to work the way you showed in the video. It scanned the entire band and you have the bands you use highlighted so you only focus on them. Please do a video on that.
It's called the Multi-SWR function. Not all of their meters have it, but for the ones that do, it's a really handy feature in checking multi-band antennas. I'll have to so a quick video on it.
@@KB9VBRAntennas nice. Well I have rig expert too. Will have to figure it out. Thank you.
@KB9VBRAntennas
Very new to Ham radio. Got my Tech ticket last month.
I thought this antenna, or an inverted V, might be a good "first" antenna 📡 for me to get started on 10-meters then other bands once I get my General ticket.
Do you use any sort of lightning 🌩 arrestor/grounding with this antenna where this feedline comes into your house? Any advice would be greatly appreciated.
73s
Tom
KF0 OGU
Is there any concern regarding RF fedback?
In the 15:17 mark of this video you stated that we could put up a 10-40M antenna for as little space as 33 feet of space. Does that mean the wire would be 33ft in total for the 40 meters or will it be the normal 66ft for 40 meters?
There are two styles of end fed antennas, end fed half wave and end fed non resonant. The random wire antenna in this video is the non resonant type. So you need a length of wire that is not resonant on any of the bands you wish to use. The 66 foot length would be resonant on the 40m band so it would be considered an end fed half wave. You can use it on the fundamental and the harmonics, usually without a tuner. The wire as short as 22 feet is considered an end fed non resonant antenna. You can use it, with a tuner, on 40m and bands above it. Without getting too deep into the weeds, a non-resonant antenna typically has a lower impedance than end fed half waves, so even in using a tuner, you still receive a high level of efficiency as compared to an true end fed half wave.
So I have a 22.5m wire with a 3.5mm bannan plug on the end of it connected directly to the center of the coax connector on my ft817nd. It seems to receive volmet and ft8 from all over the show. No tuner. Is the tuner only needed when transmitting ? Or will it improve rx too?
Very informative video! For my @home random wire antenna @20 ft of height in inverted L-configuration, I use 84 ft with a 9:1 UNUN. About 30 ft of RG-8X coax runs into the home (shield used as a counterpoise). Near the connection to my multi-switch (for multirigs) a rf choke. Works well on 80-6 meters. I can even couple one of my rigs to the random wire antenna on 160 m, but it is horribly inefficient (haven't made any QSOs yet). I plan to try a 22 meters (71.5 ft) random wire with a 9:1 UNUN for a portable Hamops. Thanks & 73 de AE5ZX
How do you determine the length of the counter pose wire, 25 feet long. Does it matter much if it is longer or shorter? Could an insulated counter pose wire be buried 2 or 3 inches below the sod? Is a ground rod connected to the counter pose side of the 9:1 unun?
I’m thinking about trying a 74 foot end fed with a 9:1 unun, running the wire along the bottom roof tiles on my roof. I’m not sure how the end fed antenna will work when it’s in close proximity to my roofing tiles.
I’m not sure how much electrical noise the end fed antennas will receive. I’ve heard that they receive more electrical noise than resonant dipoles. I assume it’s less electrical noise received with an end fed antenna than a vertically polarized antenna.
Great as usual. Thanks.
I have a ground rod and ground distribution block right where the antenna would hit the house. Is a ground better or worse than a counterpoise? Thanks.
And earth ground and a counterpoise are two different things. The ground will provide a bit of lightning protection, but isn't a substitute for a counterpoise as the RF conductivity is not very strong.
@@KB9VBRAntennas Thanks!!!
Hi, enjoyed the vid. I would like to know how I can check out my 9:1 unun if I do not have an analyzer?
I cannot understand why those making videos on wire antenna seem to never discuss wire length adjustments due to the velocity factor of insulated cable.
Velocity factor for an insulated wire, like the 14ga stranded that I used in the video, is 4%. I believe I mentioned in the video that I don't calculate to velocity factor but instead will trim that 4% when I test and tune the antenna. That gives me a little extra wire to play with when installing an antenna.
Hi
My 130 foot, 80-10(my antennas), 49-1 efhw works great. I made and hooked up multiple counterpoises to the ground rod, making 80 work very well and 160, yes 160 work decently!
But, My antennas sells a 173 and a 202 foot efhw with a 9-1.
Would the extra length improve my bands? Especially 80 n 160?
Adding more wire can increase the bandwidth of an end fed random wire antenna. But for 160 meters, you run into a problem past 202 feet as there aren't any good lengths that will match all frequencies udel.edu/~mm/ham/randomWire/.
But, if the purpose of the antenna was only for the 80 and 160 meter bands, you could do the wire lengths calculations specific for those bands and ignore the higher ones. That would give you a wealth of compatible non resonant wire lengths. While you are at it, pick a toroid with the best low band performance and maybe stack two or three together for better saturation resistance.
Thanku
Would you say then, to stay w my 49/1 at 130 feet, since its working well, or go to a 9/1 random length at 173 or 202 feet? Will I loose efficiency on the higher bands vs my 49/1?
Llastly, with my 49/1, can I solder additional length wire onto the existing 130 feet, and if so, how much would you suggest?
Thanks much
William
Very helpful and detailed. I wish, however, more was passed along about configuration and length of counterpoise. There’s a lot of confusion on this subject. Some say 1/4 wavelength on lowest band…others borrow the .05 wavelength from EFHW antennas. It’s confusing.
I think it gets confusing because a lot of people overthink counterpoises. I've found that almost any non-resonant length of wire works fine. If it's laying on the ground, the length isn't going to matter a whole lot.
Works fine lasts a long time
Can the same Magnet copper wire that you are using in this video be used if I had the FT240-43 instead of the FT140-43 that you are using in this video?
Yes it can. The FT-240 will have a higher permeability so you can run it at higher power levels. The 18ga wire will be sufficient for 100 watts, but if you want to do more, or use it 100 watts digital, I'd switch to a heavier magnet wire, like 14ga.
@@KB9VBRAntennas Is there any material that I should not use for the bracket that I will zip tie the toroid core to?
Great video. My question is, how long should I make my counterpoise. Are their any rules or charts for this ? Thank you
I don't think there are any hard and fast rules, what I would works best is a counterpoise that is roughly half the length of your non resonant radiator.
I'm looking for a good single wire antenna for receiving. What would you recommend?
I would like just the 9-1torid/transformer if one is available
Thanks, I want to try one but I heard they don't perform as well as an EFHW or Dipole. Is that what you have found also?
Of the three antennas, the dipole will have the best performance as it doesn't rely on a matching transformer. As for efficiency between an EFHW and a non-resonant antenna, I think they are pretty equal. You may get slightly better efficiency using a resonant piece of wire, but the losses in a 49:1 transformer will be greater than in a 9:1 transformer, so their overall efficiency is about equal. I wouldn't let someone tell you that an antenna is inefficient stop you from trying one out.
do you need a transformer for rx only? Eg. RTL SWR application?
For receive only a non-resonant, or random, length of wire works great. The more wire the better, but something 29 feet or longer will do fine for almost all of the shortwave bands. A transformer isn't necessary.
Nice video, Michael! I love the compactness of the random wire. Unfortunately, it really necessitates a tuner and I do not have one. Maybe I'll build a 40m-10m RW and see what I can get away without a tuner. U-rah-rah.
With a careful deployment and the right counterpoise length you may be able to get your SWR below 2:1 on most of the bands.
Great video, thanks.
What if I do not have the space for a counterpoise? Do I have to have the counterpoise?
For non-resonant or random wire antennas, a counterpoise is necessary.
just let the counterpoise hang down to the ground. Works fine on a 15 ft high antenna
Great Video... I have a big yard. I would like to have a full wave, end fed, 160m antenna. Does anyone make a kit for this? 73
Myantennas.com has some pretty beefy transformers that would work great for a 160m end fed half wave antenna.
I wonder, can a wrought iron fence used as a random wire antenna?
Possibly. There's lots of examples of people using large random objects as antennas. It would depend on how well the sections are connected.
The sections are welded together. I would try to use it as a receiving antenna only. Would I need a 9:1 unun? To where the center connector should be connected? How about the ground?
I own a 43' vertical which is great for 40-10m, but just so-so on 80, and not-so-good on 160m. So I just ordered an EFHW 80-10m from MFJ. But I really want to get on 160m, so I ordered all the parts for a 9:1 unun.... & I will experiment with a long wire vs the efhw from MFJ. I have 1.5 acre lot with lots of oaks in the 40-45' height range, but the trees are so dense it's a challenge to string a 40' high wire thru them... Doug, K5DHL
I'd love to hear what you find out. I love oak trees because they always seem to have a limb at the right height for hanging wire, but they are also dense and scraggy and tough to get wire through.
Very good presentation. I am interested in this antenna, I do activate a few parks and stay at campgrounds for several days. This antenna will work on the POTA bands and I can check in on the 80 meter nets in the evening without having an antenna running half way through the campground! 73 KI5IMV.
Where can I find “600” ohm ladder wire ? I’ve looked at Home Depot , MFJ , and MTC and still nothing . Closest I find is 300 . Can I Double it to create 600 ? Errr
300 and 450 Ohm window line is pretty common, but the 600 Ohm ladder line can be more difficult to source. Back in the day, most hams made their own with homebrew wood or plastic spacers and 18 ga wire. I did find a source online if you want to purchase some: www.trueladderline.com/w7fg-design-600-ohm-open-wire-feedline/
EARCHI- emergency amateur radio club of Hawaii sells them with correct length of wire for about $50 already assembled I use a fiberglass pole, 32 ft , from Jackite, $75. I use it as a vertical antenna. Add coax and your good to go.
Would this work with a Xiegu G90 with the built-in ATU? I'm new (very) to HF.
Yes it will. Properly constructed, an end-fed non resonant antenna will match with most internal tuners.