9:1 UnUn / BaLun Antenna and Counterpoise for Ham Radio
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- Опубліковано 7 вер 2024
- In this video, we discuss 9:1 End Fed Random Wire Antennas and the use of a counterpoise.
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TheSmokinApe
First! :D
Yes you are!
@@TheSmokinApe Good video, it's nice to see the actual difference with the graphs. I did the same thing with my K6ARK 9:1 antenna, 43' radiator, and 17' counterpoise and it worked great for QRP. When using random wire, always use a counterpoise, otherwise you're just warming up a choke with RF. :P
Yeah, I never understood why so many people say not to do it 🤔
Well Played!♡♡♡
You'll note that Ape says, "Howdy" just like in his home state of Wyoming. All kidding aside, I don't think there can ever be too many videos on toroids, core types, and windings. I always pick up something new - either a fact, emphasis, or bit of practical advice - and this video is a great example providing all three to me, at least. Thanks, Ape!
Too funny, thanks for Jim... glad you liked the video 👍
Thanks Ape. I am going to add this antenna type to the future to-do list. Looking forward to seeing the build.
Thanks Keith, here is the build video for an EARCHI I did a while back: ua-cam.com/video/9KPZO2-K76g/v-deo.html
Great video and experimenting with wire antennas is probably one ☝️ of the most interesting 🧐 aspects of ham 🐷📻radio, you never know what’s going to pop up 🙈🙉🙊.👍✅
Agreed, thanks for watching Mike 👍
Nice experiment! I can only confirm that the 9:1 ununs work really nice but the counterpoise and the ATU is a must. Some 9:1 ununs are called by their manufacturers “the magnetic balun” but after looking inside of it I found just the same trifillar unun :). As it comes to the 43 ft wire , I have pretty positive test results despite this length is not listed on the “good/bad lengths” list. With 9:1 unun , 9m (27ft) counterpoise and the CGJ-100 ATU I had no problems to find a match on all bands from 160 to 10m bands. Naturally, one can not expect any high efficiency of such an antenna on 160 or 80m but it is working and real contacts were made. Good luck in your further experiments! 73! Linas LY2H
Thanks for the reply Ly2H, these 9:1's are some of my favorite antennas.
Good video...I have an eflw with a 9:1 unun where the manufacturer says no counterpoise needed, use the wingnut for a ground....but now you got me thinking to experiment.
Give it a try, what's the worst that could happen? Thanks for watching Stephen 👍
You have a gift for explaining things.
Thanks
Thanks No Code, I try to make the content consumable 👍
Very interesting charts or test results! Thanks
Glad you liked it!
I love your antenna videos and seeing you on "Coffee and Ham Radio". Keep up the good work.
Thanks MyBall, glad you like the videos 👍
Thanks for the excellent advice. I'm in a similar situation. I bought Nelson Antennas 9:1 UNUN off eBay to use with my EMTECH ZM-2 tuner (no tuner built into my QCX-mini) and I'm quite impressed with the combination. The ZM-2 would tune 29-foot and 41-foot slopping antennas on 40 and 20 meters, but the controls were touchy. The 9:1 pulled the impedance down enough that tuning it onto those bands with a NanoVNA was easy. Simply move the SWR dip onto the bands with the left knob on the ZM-2 and tweak it with the right knob. Sometimes attaching a counterpoise helped to lower the SWR. In the future, I'll be taking your advice and orienting the counterpoise in different directions to see what difference that makes. A couple of tent stacks should keep it from coiling up.
Awesome story Michael, glad to hear the video helped you out!
Outstanding and very helpful video!
Thanks Craig, glad you liked it 👍
thanks for the analytical charting backing commentary. W8JO
Thanks John 🍻
I had heard to always use a counterpoise with a random wire antenna.👍
That's my policy!
Another good video Ape! Have you considered trying a 16:1 rather than 9:1 b/unun for this configuration? Based upon your optimized (purple) sweep, 40m (highest swr) is ~4.3:1 swr at center and might be reduced to ~ 2.4:1 swr (measured swr x 9 / 16). with a 16:1 (4 turn) b/unun. 80/75m might drop from 3:1 ctr to ~1.7:1, 60m to ~2.3, 40m to ~2.4, 30m to ~1.2, 20m & 15m to ~1.01, 12m to ~1.5, 10m Tech portion to ~1.4 and the FM portion to ~1.9, 17m would dip below 50 ohm and be ~42 ohm / 1.2 swr. Food for thought. Remember, just because something works doesn't mean it can't be improved upon. BUT there may be some reason this wouldn't pan out, I've played with some antennas through the years but I'm no LB Cebik (RIP), and you have much more experience with these antennas and b/unun's than I do. 73s mike N4ONL
Hey Mike, sorry for the late reply. I have seen the 16:1 used on loops and stuff but never made one. I'll look into them more and possibly do a video, thanks for the suggestion.
Nice job! Enjoyed the build and post-diagnostics.
Thanks!
Great video as usual
Thanks for the help putting it together 👍
@@TheSmokinApe Anytime
Quality Content, TBH best video I have ever watched on this topic, helped a lot,
Love Abysmarl
Glad you liked it!
Excellent video. Just started to experiment with random wires and C.P.s and found this very helpful. Just subbed to your channel. Looking forward to seeing what else you have here.
Welcome aboard! Thanks for checking out the video and the channel Firewater...
Thanks. Very interesting. 73.
Thanks for watching Mike 👍
👍 nice job
Thanks Izzo 👍
Hi great video, now can I plug my SDR into one of these ? wow great video, I always learn more than what I expect from you, sir thank you !
Just use coax with the correct adapters, lots of SDR folks use 9:1 antennas like this 👍
Oh, I want to argue too! That's not "maroon", clearly its burgundy. I even used "quotes" because I'm really smart.
Exactly
Thanks so much
Great video
Glad you liked it!
KD2QOJ. Great information to think about
Thanks William 👍
I am assuming that this experimentation was done after the best SWR match could be achieved with the actual length of wire for the antenna first?
We did not as a random wire isn't supposed to be resonate on any ARS band. It's a good question and a fair point though 🤔
New to antennas, so thanks and forgive my questions if you already covered here or elsewhere. Could you include images of where/how you attach on the next video on this topic? For example, I just built KM4ACK’s efhw antenna; where would you attach a counterpoise on that antenna? Would you think it is needed on an antenna with a 49:1 toroid? I realize I am talking about an efhw, vs a random wire. Thanks!
Hey Ryan, I typically use a counterpoise with bith EFRW and EFHW antennas. You connect them to the ground lug. Thanks for watching!
Hi there
My experience with 9:1 unun and 84’ of wire lenght and without counterpoise is great regarding swr exept 20m.(1.8)
But eficiency is very bad specially in the 10m band.
I like 9:1 antennas because of the ability to use them on multiple bands but to your point efficiencies can be a concern. I have a few videos where we measure the loss of the cores, here is one of them: ua-cam.com/video/6j1Yc1Y4Ly0/v-deo.html
Great video ! Just happen to be putting up a 128’ EFHW and I am curious about how to figure out what length the counterpoise should be?
I always start with 17’, 1/4 wave for 20m, and work from there. BUT, I’ve never put up one that big 👍
I know you say to use a 17’ counterpoise wire. But wouldn’t that be the same as using the coax as the counterpoise and then choking it at the radio end? I’ve never used a 9:1 random wire, but I may have to buy one just to try it out. Thanks Ape!
Hey Trucking, no it’s not the same. The counterpoise becomes part of the antenna and I don’t want that to happen with my transmission line. Yes, choking at the radio will help but my personal opinion is keep the coax as transmission line and add the ‘poise 👍
Please provide the source for the screw-clips you used for the antenna wire in your 9:1 Unun project - where you folded the wire back on itself and secured it. Thanks! McKinney-Mike
Are there what you are talking about? amzn.to/3WVkUEK
What's ideal lengths of counterpoise wires? Is this a per band thing or is there a magic length? What's a good amount of counterpoise wires to use, is more better? Take that Ape!
So there's a lot to this. When I think of a dipole, I think about the two sides and how AC current is bi-directional with equal and opposite force. An EF antenna needs something to oppose current, and that is what we use a counterpoise for vs the shield fo the coax, which has it's issues. For most antennas I start with about 17' and adjust from there if necessary... keep in mind that I don't typically go below 40m and really only want SWR < 1.5:1, I am more concerned with resonance. When we add more and more counterpoises, I like to think of them as radials for my "ground plane". Which is kinda like an artificial ground that's "better" than the actual ground. What I attempt to accomplish is something that capacitively couples my antenna to the Earth and helps with signal reflection not signal absorption. Check these out: ua-cam.com/video/2X6bSIECESk/v-deo.html and ua-cam.com/video/orS0Qodaats/v-deo.html.
Excellent chart visuals. May I ask exactly where the VNA was connected at?
Hey RFB, the measurement was taken from the shack end of the coax 👍
@@TheSmokinApe Good to know that. TNX
@@rfburns3472 👍
Question on the counterpoise, my random length antenna is planned to be 148' in length and will span from the chimney on my house through 5 trees. I plan to use a weight and rope on the end hanging down from the last tree to take up some of the slack but let the trees move without yanking too hard on the wire. The longest free span till be 46'. The coax feeding the 9:1 will run up the end of my house to the root and then over to the Chimney which is a total length from the radio of approx 60'. My plan is to have a 1:1 unun in the line where the coax comes out of the house. My questions: 1. should the 1:1 unun be better near to the 9:1 or is just outside the wall of the house ok? 2. how do I run the counterpoise. It could follow back along the coax to the ground outside the house, or run down the roof near the 9:1? 3. What kind and gauge wire for the counterpoise? Do I bury is or hook it to a ground rod? If you have a way for me to do so I could forward a sketch to help understand what I am saying.
Hey Tim. I would put the choke at the antenna feedpoint and use a counterpoise made with 18g stranded copper wire. I would not run the CP near the coax if possible to reduce the chance of coupling, I would also put a choke at the radio end of the coax. For the length I would start with about 17' and try it out and adjust if I felt it was necessary. Good luck!
@@TheSmokinApe would i just run down the roof to the ground and bury 17 of wire in the earth?
Great data. I am adding a 9:1 EFRW 203 feet in less than ideal conditions. Actually I was impressed with the overall resonance and SWR except for 80 and 160 M. So with you advice I will add the counterpoise. Is there an optimum length for that configuration. Thank much. Thumbs up and subscribed.
Hey Richard, I always start with 17' and work from there.
❤
👍
Is there a chart to show what length counter poise to start with using the 71 foot wire? Or do you have a suggestion?
www.hamuniverse.com/randomwireantennalengths.html that should be what you need 👍
I was understanding that 0.05 wave lenght counter poise is the preferred wire length at the lowest operating frequency. Hence a measured counterpoise is better than a randomly cut wire lenght??
It's my understanding, and I could be wrong, that is the general thinking for a 49:1 EFHW. I usually start with about a 17" counterpoise and tune from there. Thanks for the comment George!
Excellent suggestion. I try your advice in the near future when it cools off here in Spokane, WA.
@@georgetimm8203 best of luck with it 👍
The correct amount of coax is also key as it is the other half of the antenna. The correct amount of coax may be even more critical than the counterpoise. It needs to be matched to the antenna wire length. Watch this. ua-cam.com/video/4lzlZxxUzM0/v-deo.html
Does a counterpoise reduce common mode current? I am not using a counterpoise and an getting a ton of connom mode current even with a mfj 915 1:1 choke.
Hey Joe. It will help with CMC, also choke both ends of the coax 👍
Stupid question: When you say you ran the counterpoise 90 degrees from the antenna, do you mean on the ground under the wire like you did with the coax, or away from the wire?
My coax runs in the opposite direction from the box and emitter wire. Should I run a counterpoise in the direction of the emitter wire? Would longer be better? (Longer than 17’)
Hey Rob. I typically keep it to 17' unless I have a problem... I am assuming that you are choking the coax, I typically run the counterpoise the opposite direction of the element but may change that if constrained.
@@TheSmokinApe I have four large ferrites on my coax at the receiver side. I tried a 33 foot counterpoise as in the opposing direction from the wire, but it seemed to make the SWR worse than without a counterpoise. Still tuned either way the difference was most pronounced below 20 meters.
I'd try 17' and see how that goes.
Oh crap I just finished my 9:1 from your other vid, now I see that the toroid should of had 18 ga wire wrapped on it. I used 14ga like a knucklehead. Will it be ok?
Yeah, it's fine 👍
I have a 50’ long trifilar 9:1. No matter what I use for a counterpoise, I cannot get 160m to tune even when using a manual tuner.
I can’t get 50 to tune 160 either, not sure how long you need to go for that one. Thanks for checking out the video Kyle 👍
@@TheSmokinApe My pleasure, you have awesome videos.
Thanks man!
This video gives great info on these antennas about midway through and lists wire lengths vs counterpoises and the correct coax length and choke point. Enjoy ua-cam.com/video/4lzlZxxUzM0/v-deo.html
I have some green toroids roughly 5/8 Id and 1” od, how do I know if they would work?
Hey Tom, never messed with the green ones. Sorry man.
@@TheSmokinApe Ok thanks and 73
With this work with a handheld ham radio?
You don’t need one of these for a handheld 👍
@@TheSmokinApe thanks for the reply and information in this video!
!♡♡♡
Thanks for checking it out Aname 👍
16:1 might be even better.
I should give it a try, thanks for checking out the video 👍
I wonder what Stan would do
LOL
Smoking ape I'm going to ask you a dumb question bear in mind I'm new at this I'm still technically studying for my license what is a counterpoise
It’s similar to a ground in that it gives the element something to work against. Antennas use AC current which flows in both directions, without a counterpoise the current will flow on the coaxial shielding which is problematic.
@@TheSmokinApe So, in functionality, it works like a ground. Allowing the access energy from the antenna to bleed off instead of being reflected back on the coax shielding will cause interference.
@@chrono581 pretty much
@@TheSmokinApe Thank you for your assistance 👍😀
This antenna and transformer makes no sense to me. You would need an antenna tuner to use this thing so why use the lossy transformer. I would connect the "random" wires to my tuner directly and forget the transformer. This would be less loss.
Hey Rick. Part of the reason you would use this antenna is that it will “work” on multiple bands, as a result folk will trade so loss for a multi band antenna. Also, whether you use a unun transformer or a tuner you are doing the exact same thing and loss is compatible as I understand. In this case the 9:1 is doing the heavy lifting instead of the tuner. Yeah have a different 9:1 that is about 1:1 on 20m and higher with no tuner required. I also have one that’s 1:1 on 40m so your mileage will vary with element length. Thanks for checking out the video Rick.
Hey Rick. Part of the reason you would use this antenna is that it will “work” on multiple bands, as a result folk will trade so loss for a multi band antenna. Also, whether you use a unun transformer or a tuner you are doing the exact same thing and loss is compatible as I understand. In this case the 9:1 is doing the heavy lifting instead of the tuner. Yeah have a different 9:1 that is about 1:1 on 20m and higher with no tuner required. I also have one that’s 1:1 on 40m so your mileage will vary with element length. Thanks for checking out the video Rick.