Will it work? Yagi with no Reflector - Antenna Design/Build/Test
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- Опубліковано 5 вер 2024
- Fellow UA-camr, 2E0UKH told me about a 2 element dual-band 2m/70cm beam antenna he built. I ran with the idea and made my own, out of arrow shafts, with an additional element. The results? Watch and find out.
2E0UKH UA-cam Channel: / ukgadget2
MMANA GAL file: drive.google.c...
Antenna Photos - SWR and Patterns: photos.app.goo...
Element Lengths and Positions:
- Driven element
- Position: 0"
- Element Length: 20.17" (ea.)
- Director #1
- Position: 3.78"
- Element Length: 19.05" (ea)
- Director #2
- Position: 13.26"
- Element Length: 18.36" (ea)
SUPPLIES:
Arrow Shafts: amzn.to/3oDgpuM
- Note: you can likely find them a little cheaper on AliExpress.com
Threaded Inserts: amzn.to/37UQhWm
Arrow Connector: amzn.to/3oFrTOA
- Note: you can also just use a threaded rod and a jamb nut or some LocTite to secure it
HARDWARE:
Nylon Threaded Rod: www.mcmaster.c...
Aluminum Threaded Rod: www.mcmaster.c...
... more durable alternative
Stainless Steel Threaded Rod: www.mcmaster.c...
Nylon Spacers: www.mcmaster.c...
Aluminum Hex Nut: www.mcmaster.c...
Key Build Tips:
- Use a drill press. Hand-drilling will not result in straight enough holes.
- Remove the anodized coating from the inside of the arrow shaft before crimping in the inserts. The coating is non-conductive.
- Apply dielectric grease to the outer part of the threaded insert to prevent corrosion.
- If you over-crimp the inserts, you'll have to re-drill the clearance hole portion and re-tap the threads.
- Be careful installing threaded aluminum rods, as the threads can be easily damaged.
Have fun building, and good luck!
K6ARK Portable Radio shirts for sale (thanks Jason!): grapevineamate...
#MNHR
I have to say the ingenuity of using threaded arrow shafts is brilliant! Looks to be very durable too. And the arrows come in all kinds of colors which makes it look high tech and personalized.
To be fair, I generally got the idea from the Arrow antenna company's design which uses a threaded rod fixed into one element, and a threaded insert in the opposite element. Instead, I mounted the threaded rod to the boom.
I guess it’s time for a diy yagi build for 2m activations. Thanks for the details. 73
Great homebrew Yagi video and instructions. Order all the materials and will be making one for myself and my daughter! Thanks for sharing 🙂
Collecting all the parts would take time some don't have. You might find a retired senior with the right skills and sell these online as a kit.
I built something almost like this but not for satellite work. My first antenna when I got my ticket in 96 was a ladder line j-pole, then, since I am a bow hunter, I took a bunch of aluminum arrow shafts and a piece of a cb vertical antenna as a boom and made a beam. If I remember right it was a 4 element (reflector, driven and two directors) and mounted it on a pole outside the window. I would turn it to whatever direction I wanted to talk. This video brought back some memories of that build. Might have to do that build again. Thanks for sharing. Juddie - WD8WV
I like this antenna.
Can you do an update review?
Questions: would you change anything? How does it compare to the store bought 2m/70cm Yagis?
etc etc?
This topic is still very much relevant. Also...your ideas on fox hunting antennas including I believe it’s called Doppler.
All good stuff!
Thank you.
It performs well! I bring it regularly for an ultralight directional gain antenna for 2m. I have built another antenna for satellites with more gain and cross polarization for better isolation between 2m and 70cm and more often use that for satellites now when I'm not concerned about a bit of extra setup time and bulk to carry.
My design has less front to back ratio than many of the typical yagi designs and dual band log periodic antennas, for the trade off of only having 3 total elements. Every antenna is a compromise in some way, so pick the one that suits your needs.
@@K6ARK thank for the rapid response! Have done a video on the newest antenna? If not would you please? I just got my license at 67 and am very interested in making my first contacts ever to be with the space stations.
Thank you for your help!!!
Very neat! The use of arrow shafts is genius.
Just worked Sudan on RS-44 Satellite using ELK antenna log periodic.. keep up the good work Adam, de Ei2iP
Hey Adam, any other way you might think of for asolating the driven rear element from the beam? Can't find the threaded nylon rod in my country. And Im absolutely eager to build that antenna. Its so cool.
Cool build Adam. FYI, jealous of that drill press ;)
I have been thinking of extending my Arrow Antenna out another three feet with just some more director elements. I didn't think of crimping also. Way to go. Glad it worked and hope to work you again.
Yes, if you want the elements conductive to the inserts, be sure to remove the anodized coating first. I use dielectric grease to prevent corrosion inside. I over-crimp mine which actually distorts the threads, but I re-drill the counter-bore and re-tap the threads and it all works out.
@@K6ARK you can build another one and make phasing harness wich will attach the two yagis to gather and mount the yagis on a boom then use a cheap camra tripod for to hold it and it makes a great sat antenna setup that is how i get sstv from iss when it does slow scan tv. if you need links i can send you a link that shows how to build the phasing harness
Nice build quality. This just became a priority build for me.
My already high respect for Adam just went up further when I saw the Single Malt tubes ;-)
I mean, how else am I supposed to store my antenna parts?
Hey Adam, what did you use to crimp the arrow shaft inserts?
Looking at the antenna and those threaded inserts, you could put more on the end and make it for 6 metres. Use the different colours to denote the band. Or cut it for UHF and have the VHF part added on. Might work then as a tri band antenna. Also my work for the 4 metres band in the UK as well if adding them inserts work.
for sure it will work, my HF antenna is based on that principle, single dipole with a single director, no reflector. This gives a little bit more punch to the front of the antenna but not much f/b rejection, it is more efficient than a full size dipole inv V at the same height and it works well !
Nice antenna. I have an old golf club someone left at my house years ago that I might try and make into one of these.
Do it! It's a fun build and a simple, functional portable antenna. With a golf club shaft, you could even add a reflector for a little more gain and better f/b ratio.
Great video. I loved the detail and will make an attempt at it myself. Take care 73, Tom KC3QAC
Really nice work. I don’t do VHF or UHF but it’s always great to see homebrew stuff working. Thanks Les g0nmd
Cool project! I may have to try this one myself, assuming I can pull together all the tools required.
Thanks for sharing. Just finished mine. Had to tune the elements a little, but I think I know why. Seems like it's got pretty good front to back based off of repeater IDs.
I live on a remote area and your Yagi Uda sounds great. N0QFT
Adam, This is the most straight-forward yagi build video I've seen. Thanks again for making it simple and showing how you do it in such style. 73 - KI7WJP, Eric
Bonus: it actually works too 🤘😁
A few friends have built this design with great results. I think it's a solid option for portable, ultralight use.
@@K6ARK gonna have to try it!
Awesome build! Now on my list of things to do!
Thank you very much for this video, very inspiring!
Nice work!
Good video. I’m inspired to make one with what I have.
Nice job for a home brew no doubt.
Try the 5 element long periodic 2m/70cm log periodic that’s almost identical in construction and not only is it dual band, used horizontal, or vertically polarized, but also you don’t need a duplexer.
73
Cool. I have not built a log periodic yet. Is like to...
This one is also dual-band. No duplexer needed for this one either. The drawback to the log periodic is the greater number if elements for equivalent gain.
We gotta get that boy a drill press vice! It would make your life so much safer and easier! (ever get your fingers whipped?)
Nice build / design technique! Love the riff!
Thanks Phil! The antenna, and the video for that matter, came out great and works well for a 13" boom portable beam that weighs in at under 6 oz. It's hard to justify leaving it at home!
@@K6ARK what size was the nylone spacers the link u had for them dont go to the page you got them threw
@@AndrewMurphy8383 www.mcmaster.com/nav/enter.asp?partnum=94639A534
1/2" by 1/2" with no. 8 screw size clearance hole.
A really nicely designed antenna, very well engineered. 73
I heard your activation last weekend with that beam, but I couldn't get back out to you. I'll have to try building that one. KN6LMT 73
It seems I forgot to post about it here and only tagged Adam on Twitter, but a few weeks ago I made a tape measure version of this with the same dimensions, so those of you who are DIY or financially challenged can take these instructions and make one of these for about £5 (which is ridiculous) assuming you have some length of coax feedline and a BNC connector spare.
I have successfully worked SO-50 and AO-91 with it, but the Scottish winds over the last few weeks have taken their toll on the prototype construction, held together with literal sticky tape. So it’s time to get some threaded rods and make a proper one.
The wind also plays havoc with the pattern/SWR as the elements bend, so all tape measure Yagis wont last as a primary antenna but they’re a good test nonetheless.
Also the ends of tape measure Yagis are fucking lethal. The awe of the families and 7-8 year old kids watching me work a satellite in the local park was curtailed somewhat by me running over a few minutes later asking for some tissues having sliced my hand on the end of an element.
Thanks for sharing - some good ideas there.
Very well done, cool project!
Watching this video again and having had a go at homebrewing a few Yagis, I was watching you drill through the arrowshaft boom. I remembered one problem I always seem to have is drilling the different holes through round section booms all at the same angle. Unless you drill them all at exactly the same angle, the different elements do not line up properly and the finished antenna has a twisted look. You don't get this problem with square section booms. If you have any good tips on how to accurately drill the through holes along round section booms, please let me know.
idea: make a jig tool. Thread a piece of threaded rod into your drill backer board to hold your boom in the correct position. Drill your first hole, push the threaded rod down through that hole, then slide the backer board down to the position for the next drill hole
@@gx1400 Excellent, thank you. Sounds like this should work.
Happy New Year, WOW Just WOW. I am new to ham and i really want to build one of these. I need to get myself a NanoVNA. Then my plan is to build a Slim Jim, Yagi and a Dipole for 2m SOTA and SAT, I already have a Anytone 878 and a 8m Fishing pole just need the rest now. Hope to catch you in the log somewhere Motters M7TRS 73's
Rather than the dipole, consider an extended double zepp if you are ok with the larger size. www.westmountainradio.com/antenna_calculator_zepp.php
Don't forget to account for velocity factor in cutting the twinlead section (it should end up about 8.5 inches for a 2m antenna. These things work great. I hang one vertically from a telescopic pole for omnidirectional coverage.
@@K6ARK Mind blown OK will have a look into this. I really love the idea of being somewhere sort of remote on a big hill and a homebrew antenna. Super thank you very much for the advice will have a look.. Have sooooo much going on around my head regarding all this HAM stuff. Again thank you. M7TRS 73
Adam - it definitely worked for me 40 mile contacts in two directions FT-60 5W. Thank you for your great direction, I wonder if the McMaster-Carr threaded nylon is more durable than the Ace Hardware Nylon. I went strait into a BNC instead of a SMA then to a BNC (it is what I had to work with.
thanks for your Yagi antenna made plan . this is BD7PMJ 73~
Well done 👍
Nice!
This probably is a really noob question but I have spent 30 min searching already. what are the right ring antenna connectors, coax line, and BNC adapter did you use? More generally how do you connect your radio to this antenna. The way you connected it to your radio and in the photos looks very professional. Thank you for all your hard work!
Very cool
While the yagi works, its not a great match with the result that the coax and even the hand holding the boom become additional radiators. First it needs "matching" raw coax to the dipole works but not the best. Then there needs to be a balun and or choke that does not exist. At 2 or 3 elements there is not a lot of gain, but a reflector does stabilize the radiation pattern and a hand on the boom will have less effect. Similarly the First Director performs and impedance matching function as well as a focusing lens. Its the combination of reflector and 1st director with a well fed, feed , balun that clean up that pattern.
To go a step further, changing a single element driven element to a folded dipole broadens the resonance and swr to beyond that of optimized length elements. A longer reflector and shorter director can also broaden that resonance for a small decrease in gain. The antenna shown showed good polarization that indicates that this crude simple feed arrangement worked.
Thank you for the input. I'd love to see your design for a dual band 3 element yagi with a simple 50 ohm match. I do have a choke at the feed point to help eliminate to coax from the equation.
CW FOREVER
Super cool
Never mind on the other comment about the antenna. I found it lol. 73
I'm trying to find information on the design of close-coupled 2 element yagis, very similar to what you reference as your inspiration for this. My google-fu is failing me and I'm not finding any useful design info. Any pointers?
I've heard that they can be made to have a very clean pattern, and want to build one for direction finding (on 121.5 mhz)
Love the DIY videos! Great job - N6BFG
I love this project, going to have to order some parts and give it a try. Thanks for sharing Adam. KC7UJO
Does the length of the handle beyond the driven element matter Adam?
Hey Adam. Very nice and clean build. Why did you not include boom length in your mmana model? If additional handlebar is not insulated from then antenna boom it counts like a boom. Just thinking about it because final build looking good on miniVNA. Have a good one :)
In my modeling in MMANA, the extra boom had no impact on the pattern or resonance so I removed it. 🤷♂️
Maybe I didn't model it right? The VNA plots matched the model incredibly well though.
Amazing work Adam, thank you very much for sharing. Did you try to check the antenna with a VNA ? curious to see the graph and compare it to what you got in MMANA .
Yes! It was incredibly accurate.
2m: photos.app.goo.gl/cMiPCN6HPM37KZZ98
70cm: photos.app.goo.gl/TWcAH5dMsRPMF78v7
What is the end to end length of the directing elements? I am going to make mine solid and don't know how long this arrow connector is.
WE9O
What Discord channel are you on where you discussed this?
The position measurements are always starting from the starting position "0" right? Sorry, just to be sure. Thank you Adam
Yes, you've got the right idea. Position zero is the starting point for all of the measurements.
Hey, i have that same project pat.
Have you seen that folding yagi on aliexpress that uses small whip antennas for the elements, Search the following if you are interested. Claims 6 db gain. '2022 Latest Upgrade UV Yagi Antenna 25W VHF 76-350Mhz , UHF 250-500Mhz , VHF 6DBI , UHF 8DBI Mini Radio Antenna'
What's that crimper that you use on the arrow shafts? Or is there a standard designator so I can look for jaws for one of my crimpers? Thanks
What kind of crimp tool are you using? I have tried a few times with simpler crimp pliers and have not been able to get a tight crimp on the insert.
I have been using a crimp tool intended for coaxial cable - I believe RG58. It is easy to over-crimp with that tool, but I just repair the insert by re-drilling the bore and re-tapping the threads.
Great design! No hairpin match required unlike tape measure yagis?
Correct. It's a 50 ohms feed. Put a choke (a few turns of coax through a toroid) at the feed point to prevent the coax from interacting.
Very nicely constructed video tutorial. VK3TMP
also working on 14 elements reflector less
Can be added a reflector? What's the advantage of not using a reflector? Just to understand! :) Thank you
The design with no reflector is resonant on 144 MHz and on 440 MHz for dual band use, and for FM satellite operation.
Hey Adam, I have an idea about a built video for you. I enjoy your videos a lot, and have recently found out about a really nice antenna for vhf/uhf ssb ( which can give great distances on SOTA/ POTA activations). The antenna is the wt4e antenna, you think it could be be a good homebrew project?
Thank you Carlos! I appreciate the recommendation. I had not previously seen that specific design. It is a dual band version of a Halo antenna. To make it dual band, the designer simply put two of them back to back, one for each band. These antennas produce about unity gain (0 dBi) but with horizontal polarization and an omnidirectional pattern. Most other omnidirectional antennas are vertically polarized, and if the other station is horizontally polarized, polarization losses can be on the order of 20 dB. I could see an antenna like this being very useful for mountain top contesting where high gain isn't needed, but when horizontal polarization and an omnidirectional pattern are desired. I could see this being particularly useful as a receiving antenna that is not directional to listen for stronger stations calling, then to use the yagi to reach out and complete the contact if the Halo isn't sufficient. Cool antenna, and I may have to build one of these at some point. If I do, I'll definitely film it. Thanks for the comment.
Was that your coax crimper you used to secure the insert
Good eye! It is indeed 😆
Amazon cart. ACTIVATE!! Cool design. I may try to make a 3-element with a reflector. What did you use for a handle? Looks like cork(s).
Great question. Yes, cork. It's a fore grip from my fishing rod building supplies.
Link...
www.mudhole.com/Tapered-Cork-Foregrip-3-Super-Grade
More options...
www.mudhole.com/Components-Rod-Building/handles-grips-components/Fore-Rear-Grips-Handles?page=3
Here's one more that would be great...
www.anglersworkshop.com/Fly-Rod-Cork-Grips/CG35-Rear-Grip
what crimper are you using on the arrow shafts. 73 W4YF
Well it doesn't NEED a reflector. Just a director. I think.
Great to see how you are doing that, how is this crimping tong called? And where can I find one? 73 PD1MV
I am using a coax crimping tool. I have not been able to find inserts that provide an interference fit, but that would be the ideal solution. Be sure to remove the anodize coating before crimping for good conductivity.
Also, you may find that crimping deforms the threads. I usually re-drill the countersink portion of the hole, and re-tap the threads after crimping.
What formula did you use to know the length of the Coax?
What is the power rating?
I was unable to find the nylon threaded rod in my country, so I made your antenna with a little twist, a gamma match. It,s resonant very high on UHF 455 mhz, any tips on how to lower ot to 438 mhz?
Carlos, I'm not sure. Double-check your element lengths and diameter. Smaller diameter elements will need to be longer. What does your SWR curve look like on 2m?
@@K6ARK 1.08 on 146.400 but had to cut the driven element a little shorter because I used thicker wall Aluminum. Left the driven element at 19.48"
Ok... another thought: I'm not sure how the gamma match affects the multi-banded nature.
On mine, adding a choke to the feed point improved 70cm, but I believe the gamma match should be acting as a balun for you. Still, might be worth a try.
@@K6ARK Thanks Adam, will try a Balum and let you know. The antenna works fantastic on vhf, got several contacts about 15 miles on my handy with only 1 watt.
Awesome video! I'm in the process of trying gto build a portable yagi for SOTA. Glad I can across this...question though...can this be built without the nylon insulators, and the boom be made of square aluminum tubing? Thanks again for the great stuff man... KN4WXI
Yes, so long as you still insulate the driven elements from the boom.
@@K6ARK awesome man! Thanks again for the great info and content...I always learn so much from your vids...
@@K6ARK Hello Adam...I have all my parts together ready to build the antenna, but have another quick question. Just to be make sure I'm understanding ok...the distance between the driven element and director #2 is 13.26"? Or is that the distance between D1 and D2? Thanks again for all the info you've given me so far... KN4WXI
@@justinshephard5262 driven to D2 is 13.26". It's a very short boom!
@@K6ARK thanks again man...I thought that's what it was but wanted to make sure before I started cutting ...
@K6ARKPortableRadio is there anything isolating the threaded rod for the elements from the boom other than keeping the nylon isolated appropriately rotated? edit: that is... if one of the driven elements takes a torque (drop it?), can the isolated turn and have the threaded rod make electrical contact to the boom?
The driven element uses a nylon threaded rod which is insulating.
@@K6ARK totally missed that! So the driven elements are isolated from the boom AND from eachother. Looks like the directors are using the alloy threaded rod, are they electrical isolated from the boom/each other?
@@gx1400 passive elements on yagis should be conductive to each other to work properly. They can be conductive or isolated to the boom.
@@K6ARK thanks for the education! Bought one of your matching units on amazon this weekend to pair up with my (in progress of being built) trusdx.
Relatively new ham and looking to learn more! Cheers 73 de KE0PRY
@@derekrowland246 also worth noting, driven elements can be conductive to the boom and each other IF they are fed differently (i.e. gamma match).
What coax did you use great antenna, will try to make it
I just used a very short length of RG-174. For a run of just a couple of feet, losses are minimal even on UHF.
whAT IS THE OD SIZE Nylon Spacers AND HOW THICK OF NYLON SPACERS ARE THEY
I used 1/2x1/2x#8
Is it ok to use glue that is commonly used for making your own arrows to secure the inserts in the shafts?
Why are the elements set for 3/4 wavelength and not 1/2? Am I missing something?
Do you mean 1/4? A yagi is essentially a dipole with parasitic elements that passively couple to the driven dipole element. Try building or modeling a dipole with half-wavelength elements. One half-wave element fed at the end (i.e. end fed half-wave antenna) drives the radiating element at a high impedance point, requiring a matching network - typically a 49:1 unun. I don't think feeding two of those end to end would work.
The elements ARE 3/4 wavelength on the 70cm band where I am taking advantage of the 3rd harmonic. The drawback is that there are lobes to the radiation pattern, but that allows me to stick with one set of elements for both bands.
@@K6ARK Maybe I misheard, I was referring to the total lengths of each element when I said 1/2 and I thought you said they were all 3/4. You probably meant 1/4 on each side of the boom.
I am playing about in MMANA now ;)
@@MarkPentler that makes sense. It's possible I misspoke or just wasn't clear what I was referring to. Apologies for that. The full elements are roughly half wavelength from tip to tip on 2m and 1.5 wavelengths on 70cm.
@@K6ARK Good news! Take your file, rescale from 146.52 to the UK calling channel of 145.5. You've just gained 0.03 SWR on 70cms! And 0.02 on 2M! But I think that's because our calling channel is 433.5 and further back down the band than yours.
So, if you're in the UK, this will get you an incredibly tiny bit better gain on the uplink than Adam is getting here, but by so little that it probably wasn't worth mentioning as anything other than a nice bonus fact.
Edit: If you can find rods that are 6.8mm in radius exactly you'll gain another 0.02! I must admit, antenna modelling is kinda addictive...
Edit: OK finally got this working with thinner elements, such as rods etc. Just had to respace things a bit, but now I have a model with an SWR of 1.175 on both 2M and 70cm, and gain similar to yours. That's with elements of just 2mm in radius. Shame you can't ask the software to aim for the best compromise for two frequencies when optimising.
Anyway, I love your channel, it's inspired me a lot.
Well of course...............There are two element Yagi's
Two elent yagis typically have a driven element and a reflector.
What is the Dimension of antenna Yagi with 3 element no Reflector
All of the design info is in the video description, including a MMANA-GAL model.
Thank you very much on video i cannot see the Dimension can you write to me
why do you use "FREE SPACE" Field plots setting?
A 2m yagi on a mountain top or pointed at a satellite is going to radiate much like the free space pattern, and it gives me the best idea of what to expect in a variety of orientations, terrain conditions, and directions of orientation.
@@K6ARK you seem to be knowledgeable. Which ferrite material would you use to wind an inductor (aka 1:1 balun choke) for 80MHz quarter wave ground plane antenna? Material 8mm aluminum tubing, Tx 50w.
Double check the specs, but a -43 should work. I'd probably use a 140 size.
toroids.info/FT140-43.php
Application Freq Range
Wideband Transformers 5 - 400 MHz
Power Transformers 0.5 - 30 MHz
RFI Suppression 5 - 500 MHz
Which line I'm supposed to look at, RFI Suppression?
^ bump
WHAT IS THE LINK TO THE CRIMPERS U USE
Can't find the exact ones, but these are very close. amzn.to/33bkA8f
.255 jaws work for the arrow shafts if you are careful not to over crimp. .320 jaws are probably better. If you over-crimp, you'll have to drill out the insert counterbore and re-tap the threads.
不用巴伦吗
It helps with tuning and radiation pattern. I use a few turns of coax through a ferrite.
Voll der Messie !!!! Guck dir mal sein Arbeitsplatz an...
GOOD DESIGN & FUNCTION 2M/70CM! 73 de sm6oer /Gunnar >>\
Nice work!