ฝัง
- เผยแพร่เมื่อ 13 ก.ค. 2024
- Further development of a design from the website below where a commercial 5/8ths wave CB antenna is reverse engineered. This enhanced model is tuned specifically for the 10m amateur band and also adopts a ferrite choke, which is an improved option over the air-wound choke which is also shown in the build.
The parts for this simple DIY build probably already exist in your shack? If not, they come to about £5 for the air-wound choke model, or about £10 if you go for the ferrite choke model. A list of parts:
Main Antenna = 3.5m RG58 coax + 3.25m of insulated wire
Air-Wound Choke = 3.6m RG58 coax (or) 9 Turn Ferrite Choke = 73cm RG58 coax (+ the ferrite) - a 12 Turn on a 52 or 61 core will use a little more coax, say 1m in total.
Matching Stub = 71cm Westflex 103 coax
Original CB antenna article: radioaficion.com/cms/sirio-ga...
G3TXQ chokes: www.karinya.net/g3txq/chokes/ (follow the links mid-page for detailed and updated analysis for specific ferrite types)
This is one of many amateur/ham radio related videos on my channel. Please feel free to browse 👀, like 👍🏻 and subscribe 🔔 (it's free!), remembering to hit the bell so you’re notified of new videos as soon as they're published and you don't miss out.
Part two of this 5/8 vertical series can be seen at: • 10m 5/8th Vertical Ant...
Here's a link to the Westflex-103 specs if you have trouble sourcing some: www.whwestlake.co.uk/westlake-...
0:00 Introduction
0:30 Theoretical Antenna Design
4:10 Practical Antenna Design
6:20 RF Choke Options
8:06 Antenna Build
11:02 Antenna Testing
12:29 Summing Up
Thanks.
Ian. - วิทยาศาสตร์และเทคโนโลยี
Having built this antenna, have to say it’s definitely my favourite so far, spot on frequency after build, and the performance is excellent.
Rx signals increased from s2 to s4/5, very good on dx, I’m using less output on 10 meters compared to my multiband antenna, and it tunes to 12 meterband again great results
If your intreasted in 10 meters I would seriously give this antennae a go!
Great Mark! Glad it’s doing the job well 👍🏻
I watched this after your March 22 update, both videos are very useful for building a very versatile antenna. Thanks Ian.
Thanks!
thank you very much for the video. Very explanatory and in basic details. I tried for a long time to make such an antenna by watching a video, but everything was at a standstill( hi SWR). In the end, what I didn't do because they didn't mention it was what you mention at 9:25. Thank you for finally making a great functional antenna, saving money and time and doing my hobby. I have subscribed and will watch your useful instructional videos. Honored by George from Greece
Great George! I’ve been using it just this week to work South America. Great antenna to have 👍🏻
I built it because of you. I installed it today. Very good antenna.Thank you! Best 73
Thoughtfully explained and clearly presented Ian. Great job.
Thanks Tim! Lots of videos released today, so lots to catch up on! 📺👀
Great informative video Ian, thank you.
Thanks Adam!
Very well done. Thanks for the fine presentation.
Thanks Richard! There are two follow-up videos to this one if you’ve not seen them already 😀
Hi Ian, just worked you (as G6XX) on 80m, this is the video I was referring to HI...all the best for 2023 mate
Brilliant! You just faded at the vital moments 🙄
The "broadbanding" cap and exceptionally low SWR over a wide bandwidth suggests the antenna is designed to be lossy to control the SWR excursions away from resonance. Agree?
I particularly found the feedline choke information valuable. Will grab a copy now for later reference.
I’ve wondered about that Louis. You can always dispense with the capacitor and use it neat on the one band 😀
Excellent video, thanks! I think I'm gonna give it a try too.
Great Philipp 👍🏻
Finally tried this build out in anger this weekend Ian 25/06/2022, (I made this last year when you first posted the video) works really well, definitely has better ears than my ground mounded vertical on 10m at my QTH at the bottom of a valley. Mounted it to a 10m fibreglass mast. Very broadbanded and so worked on 12m too. Thanks for the build.
That’s great! Tree now in leaf on mine, but doesn’t seem to affect it. All good. Thanks for the feedback 👍🏻
Awesome video. Question: How is the ballanced antenna matched to UN-Ballanced coax feed??? Is the Ferrite the ballancing mechanism???
@@ericdee6802 Hi Eric! You’re question was hidden under someone else’s comment (& TH-cam doesn’t flag these up unfortunately). No, the ferrite merely stops the rf on the outer coax, so defines the actual end of the antenna via this choke. It’s the matching stub that helps with the mismatch and 200Ohms. Thanks.
Ian! Weirdly I found this video off a google search on matching stubs. Great project!
Wave as you pass 👋🏻 😁(follow-up videos to this too 👍🏻)
Excellent video - Thank you
Thanks.
You definitely enjoy messing with antennas Ian. That's an interesting build and seems very broad banded. Keep us the good work. 73 Chris M0RSF
Ha ha, yes Chris. Keen to try it out in anger, but 10 quiet at the mo 🙄 Catch you on the air 👍🏻
Fantastic, thanks 👍🇬🇧
Thanks!
I built this (with the "Ugly Balun") and it turned out very well. I'll try the FT-240-43 approach in the future. I have a 10m extendable GRP pole to raise mine up and down. Thank you.
Great 👍🏻
Thanks a lot for your info
No problem. Thanks!
👍Thanks for posting video.
No probs Steve 😀
Bit clearer explained, it is easy to forget that the person on the other end does not always automatically know the bits others have left out that they think they will know. If you see what I mean. Confucius say!!! Oh Master! What you say Grasshopper?
I think Mike did the CB version didn't he?
Hi Bob and thanks! Yes, Mike did the CB one in a different style 👍🏻
Nice job, very clear and concise! Oh and I enjoyed the ragchew on 40m earlier too, thanks for the new band. next time we'll make it 20m? lol! 73, Tom G2NV/M
Hey Tom! Thanks and yes good
To catch up 😀
Have made 3 of these so far, just about the best antenna IMO. I will try one shortly without the cap. just to see how narrow it gets for fun, I use rg8mini, for the stub, no problems with 100 watts at all. I use the 16 turn choke, no common mode that I know of, but will try and measure this at some point as well , need to make some kind of rf current meter to do this. Great video, great antenna, look forward to any experiments / improvements on this design.
Thanks Mike! Yes, I don’t think I need the capacitor, so it will be interesting if you try without. Keep me posted 👍🏻
@@ianxfs will do, I never felt a cap in line would make a better element, wider bandwidth yes, but look forward to testing without it. If I could get 1 mhz without it, that would do the trick. I have a gut feeling it would receive better without the cap???
@@pixotica Have you testet it??
@@TheRiddleNL not exactly, I did do a 5/8 wire, with one vertical ground plane matched with a ferrite transformer, It worked quite well. Ie it was a dipole 5/8 wire up, with a 9 foot wire down.
@@pixotica Ah okay. I have spiderbeam pole and consider making this rollup 5/8 for 10M. Verticale dipole isn't that practical. Deleting the coax C makes the antenne More rigged.
Super
Thanks!
Hi Ian. Very nice video. Is it possible to feed the 5/8 vertical at the center and use a 4:1 balun?
I don’t see why not Cesar.
Great vid. Ian. I'll be putting one together in the next couple of weeks. The original article doesn't seem to be there any more!!. John - 2E1JBC
Ah right John, I hadn’t realised. Good luck and have fun with yours! 😀
@@ianxfs I made a T2LT for 10M. as per one of your fellow TH-camrs
Tim G5TM and it works really well. I'm keen to see (hear) the improvement that this design will bring. Subscribed. John - 2E1JBC
Out performs the ribbon cable J pole..much better useable bandwidth.😊
Great Michael 👍🏻
I know this is an older post, but I would really like to see the full page of theory displayed at 0:07 seconds into the video, concerning the matching section calculations. I intend to build this design, but using 50 ohm RG8X(PE) low loss cable with a velocity factor of 82% for the sleeve, and 50 ohm RG8U(PE) with a velocity factor of 66% for the matching stub. The reason for the substitutions is, that these are the materials I have on hand.
Hi, I checked and the original article is no longer on that link. The author did mention trial and error before arriving at the measurements used. I would suggest substituting RG-58 and Westflex 103 specs with your own coax and ratioing up/down the coax lengths accordingly. Good luck! 👍🏻
Excellent presentation. I am definitely going to make one. How much power will it take?
Thanks Ken. I think it’s ok for the UK 400w limit. Higher, maybe use RG213 instead of RG58 and adjust the length for the different velocity factor. 😀
great video. what camera did you film this on please. Great quality.
Hi thanks. It’s just my iPhone 8. All the videos on the channel are from the same phone.
@@ianxfs Thanks. Looking good.
The Westflex-103 could be substituted with the LMR-400, 50 ohm, which velocity factor is 0.85 same a the Westflex cable.
Thanks.
I only have RG58 and RG213. Would it be possible to use the RG213 instead of the westflex-103?
Hi friends. would like to make this antenna soon. The westflex 103 cable is rather difficult to obtain in Poland. Please let me know how critical this cable is in this project. Is replacing it with the popular RG213 cable a good idea? Maybe you need to recalculate its length?
Hello! If you look through the comments there’s a few about different coax types. Also, if you reply to someone who sounds like they’re trying different coax, then they may reply and explain how they got on. Good luck! 👍🏻
Just curious how you can have 200 ohms of resistance at the centre if the ends aren't touching? Wouldn't it be OPEN and resistance read Infinity?
Hi. This is RF and not DC. Different properties altogether 👍🏻
Please describe what kind of rg58 did you use and velocity factor of this cable. Thanks.
Hi, I think it was Webro and vf of 66%. All RG58 will be very similar.
2:30 that 5/8 design where you say to terminate the lower part to stop common current, could have you simply build a 4:1 balun ? those are really simple to build with the exact same ferrite FT240-43. That type of balun give close to -30dB of common mode attenuation at 28MHz. A single core can handle 800W PEP. Wound two pair of 18AWG PTFE cable for 12 turns. A pair of PTFE cable is 100ohms, when in parallel it gives a 1:1 balun and when the secondary is in series, it gives a 4:1 balun. That could have complete your antenna right there if I understand what you are saying.
Yes agreed, although those using an air-choke would still need the matching stub method. Thanks.
I'd like to scale this up to 17m band and others. what would those dimensions be ?
Hi Danny. I think you can proportion the main lengths up based on the percentage difference in wavelength (be sure to calculate the real wavelength from frequency). The capacitor dimensions should be the same, but I’m not sure about the matching stub 🤔 Perhaps cut this long to start and then trim to suit….Good luck if you give it a try 👍🏻
Hmm could I use a 4:1 Unun instead, since its roughly 200ohms?
It probably depends upon the spec of the unun. See interesting G8JNJ article on the effects of different types.
What alternatives can be used instead of the Westflex? Looks like a perfect antenna for me but I can't find Westflex here in Australia.
Hi Wayne, you’d need to match the capacitance and velocity specs or adjust accordingly (and/or experiment). Not sure what your supplies are in ZL…hope you get sorted 👍🏻
@@ianxfs thanks Ian. I've just watched Mike's video and one of the comments on it recommended rg213 at 73 or 78cm (can't remember exactly). 213 is something I do have so I'm keen to build this antenna. Thanks so much for responding and posting the tutorial. 73
@@WaynesWorld69 Good luck Wayne 😀
Very good video.
I have a similar homebrew antenna for (*cough) 29 MHz, it's called a T2LT and works very well on 11 meters (yes, I do sometimes 'slum it' with the CB guys, it's where I started after all)
Ha ha brilliant Stephen! All good fun 👍🏻
At least you don't have to be so formal on CB, lots of fun, or at least there used to be!
@@BoB4jjjjs early 80’s for me Bob 😀
@@ianxfs Late 70s for me, I was naughty. Then came FM :-((
It's all radio, all that's different is what you say and how you say it. The time for snobbery is long gone.
Very clear n slick. Shame didnt get to see usage results. Whats the man made noise pick up on it like?
Hi Steven, thanks! I used it in anger at the weekend 😀 Part 2 released tonight 👍🏻
I made a halo type, square, folded dipole, from speaker wire. Air coax choke. I put this on ground and could rx most station that were s4 and above - with the bonus that qrm was not moving the needle!
@@stevenmcc6052 Great! I’ve got a loop on the ground for the lower bands 👍🏻
I have a new to me pneumatic 9m mast . When serviced and usable, can u recommend a decent directional - not a full yagi - too big.
@@stevenmcc6052 What band Steven?
Greetings friends, I need your advice.
I have a station Alinco DX-10 and an antenna Santiago 1200, I have it at home, and since I do not have a chance to make a large assembly I bought a small metal stand and a magnetic base, the metal bracket attach it near the window with some Plastic flanges so that it is well suited.
My problem is that it is impossible to calibrate the antenna and make it go down Roe .. Just lower the Roe when I hold the magnetic base with your hand. So I think there should be a mass problem, any idea?
Thank you and greetings from Andorra
(Translated with SR Google)
Hi Manel! Yes, assuming your coax and connections are ok, it sounds like you need more ground plane…more metallic surface area for the antenna to work against. This is the what the coax braid connects to. Also, make sure as best you can that the antenna is not near any objects which may interfere. Hopefully this translates ok for you 😀 Good luck 👍🏻
@@ianxfs Thank you very much for your comment.
He has also told me a colleague that I can connect a negative cable from the power supply to the base of the antenna ...
@@manclubandorra I wouldn’t recommend that Manel.
I'd like to try building this, but the 71cm Westflex 103 is hard to find in the US. Can you give me any specs on the cable... is it 1/4 wave, what capacitance, etc, as I would like to simply use RG-58 or RG-8. Thanks.
Here you go, this link has all the info you need. Good luck! www.whwestlake.co.uk/westlake-pdf/WF103.pdf
@@ianxfs thanks, but I was in still in the dark regarding the correct calculations. Unfortunately, the original CB antenna article you linked to is gone, but fortunately can still be found in the Wayback archives. After finding it today, I now have the confidence to have a go at building this. Only thing I need to get is the ferrite core. I have some T240-31's, but not ideal for this frequency. I'll be anxious to try this out for the 10 meter contest coming up next month.
@@sciencegadgetry You could always wrap an air choke if you can't find a type 43 or better core for the time-being? You could try RG213 instead of the Westflex and create a longer stub which you can then trim back based upon your tests. What I'm not sure about is the positioning of the stub along the main length of the antenna, but guessing that this isn't super-critical, so leave as-is? Other than your time, the parts are cheap so worth the experimentation....
I need one of these for 11 meters .. can you tell me how to achieve this I live in a HOA and I am pinned in to being secretively creating a solution .. help ..
Hi. You’ll find these measurements can easily cater for 11m as well as 10m. If you watch the two follow-up videos it will explain more. There’s a chance your initial trim lands close to 11m anyway and the wide-bandwidth helps. Good luck 👍🏻
Why 5/8? Where did this fraction come from? Why not 3/4 etc?
Hi. 5/8ths gives a lower angle of radiation, so should be a better DX antenna.
👍🇧🇷👍🇧🇷
Thanks!
For the w103 stub can I just use regular rg8?
I haven’t got the specs to hand Jeff. You’d need to compare the two and adjust accordingly…
@@ianxfs ok thanks.
@@jeffdyer2393 Jeff, I used the same RG-58/U to make my stub and it worked perfectly. I compensated for the velocity factor of the RG-58/U versus the WestFlex 103.
can you explain how you compense/calculate for other kind of coax, witf different velocity ?@@johnbigbooty
@@user-ub9tc3lf2z percentages. Let's say one coax is 0.66 and another is 0.80. So, if I'm using the 0.66 VF, I'll divide 0.66/0.8 and multiply that by the theoretical length. The opposite if you are working with 0.8. it would be 0.8/0.6 multiplied by the theoretical length. I hope this makes some sense, and good luck.
It looks like Hawkins stopped building them , someone should jump in , I only see T2LT without the stub ..
Thanks.
Why West flex 103? No rg58?
Hi Giovanni. It’s not my design, but it will be for the correct capacitance and inductance required.
Chck velocity factor. You can replace rg58 by CNT-400 or RF-7
You could use RG58, but it will not withstand above 300w continuous RF power (like FM or AM). Antenna Stub heats up and slowly damages itself with time. Once it gets damaged, antenna will have sudden high SWR destroying your radio or amplifier.
Got any for sale please
Hi Ian. Sorry, no. Worth a try building though. Good luck if you do 👍🏻
Web site don't work
Thanks. I wonder if it’s been taken down. Will check…
@@ianxfs I would like to download that sheet to make one
@@ironhead320 You can use the diagram I put in the video. All the measurements are there 👍🏻
btw, isnt it possible to make a 1/2 wave dipole like this, without the matching stub, and just choke at bottom? I see T2LT does this. Never seen this matching stub before.th-cam.com/video/Ak2w6diQw7A/w-d-xo.html
Yes, I would imagine so, and adjust for any frequency.
@@ianxfs thanks for the response I just spoke to somebody testing a gain master vs L2T2 dipole, and he said the gain master perform the best, so if I was going to make a gain master for 27mhz I might just omit the capacitor and just tune the correct 5/8 wavelength.
Traditionally, a "5/8 wave" antenna is a 5/8-wave element replacing the quarter-wave element, *not* two 5/16th elements. So a 5/8 antenna might be (for example) a 5/8-wave element over a ground plane. I'm not sure what the unique and correct name would be for two 5/16-wave elements, but the term "5/8 wave" was already in use.
Thanks.
Parts of this are very hard to follow... Instead of time compressing the assembly you might have just filmed it ...
Ok thanks for the suggestion. Perhaps pause the video as you build and/or make some rough notes to help? Good luck with your build 👍🏻
I agree, I'm very confused
This is a total mind blower to me.
1. Why would anyone want to pay for a 358 cm of coax for the choke balun or a ferrite toroid with added coax when they could use 263 cm of cheaper wire for the radiating sleeve?
2. CB antenna designers are not the sharpest engineers. I don't understand why we need to emulate their misguided attempts at antenna design. There are easier and cheaper designs with more gain.
Sorry, I don’t understand your reference…
@@ianxfsyou use a choke to choke the RF from floating back down the coax. That's 358cm of coax you wouldn't have to use if you instead used wire with a coil to cancel the capacitive reactance. You can get more low TOA radiation as well. I'm trying to figure out the advantages of paying more for less performance.