Hello, thank you for sharing the knowledge! To crimp the arrow shafts onto the arrow insert, what I use is a pair of coax crimpers I have from back in the day of C band satellite antenna instalation. It is a hexagonal crimper used for RG59 and RG6 F connectors.
Awesome build! I am going to attempt this build this weekend. Lacking a 3-D printer, I will make the insulators out of 1/2” HDPE sheet that I have. I’ll thread the element studs and set screws through that. To further add to compactness, you could fabricate the main boom out of fiberglass tent poles that break apart in the middle. Thanks again!
This gave me a idea. I've been looking at building a 2 m vertical dipole. Them arrow shafts with inserts would do the trick. A screw would hold the shafts mounted to a electrical junction box.
Very nice build. Better quality than I've seen and there are no commercial alternatives for your design. I've built several 2 meter beams, my biggest problem so far has been finding commercially available element "holders". I don't have a 3d printer so I was forced to search for element holders on the internet. In this land of plenty (USA) you would think you could find holders readily - but no, ordering from UK or Bulgaria was my only choice and shipping was expensive. The 3d printed holders have stl files galore out there but if you contact one of the 3d companies willing to print out your stl - you'll get charged galore also. Really if want to DIY a VHF antenna, once you find a good element holder / substitute that you don't need to modify, the rest is cake.
There is an insert glue for arrows. But you can GENTLY heat up the end of an aluminum arrow, so it expands. Then just slide the threaded insert, inside the arrow. When it cools, its rock solid. If you over heat the aluminum with a torch, it will disintegrate! Some glues may or not allow electrical contact!
This looks like what ARROW does with their antennas as mine have a slight outer diameter difference at where the insert ends (0.1 MM difference) I have noticed a dimple on some older arrow antennas which suggest they were crimped.
Ferrule glue is what you're after. I'd give you mine if I could find it. I suppose they yet use aluminum arrows, or at least that some of those glues are yet out there. HINT-- get some field tips to screw into he insert such that you have a nice handle/heat sink and to keep from getting glue into the ferrule. Has been years since I messed with archery-but used to hunt and shoot the 3D tourneys. Also--a heat gun is better bet for controlling your heat than a propane torch-but either can be used.
Okay, I heard your next two lines, suggestions if you get ferrule glue: you'd be depending on the flange of the ferrule and the end of the shaft for continuity and to that end I'd heat the ferrule and touch it to the glue where it just picks up enough--and keep it on the back end. Then shove it into the arrow but stopping just short of fully seated. Then I'd clean off any ooze that squeezed forward in order to maximize Al to Al contact at the tip. Once it's cleaned off you can then heat the tip of the arrow and slide the insert fully home (and maybe no more seepage will compromise your continuity... It's a lot faster to do it than to type it out. If it doesn't work, heat it up, pull it out, clean all, and try it again.
N6EF-Thanks for some great ideas. I built something similar which I saw on Chuck, KK6USY Radio Adventures', channel which was inspired by Adam, K6ARK's build. I used some generic shafts I found on eBay and some inserts which were a bit loose. I used a center punch and put a dimple in 4 places around the shaft to keep it from moving. It's not super tight, but it doesn't move much. You can punch it too much and deform the insert to the point where you can't get the screw inserted which I found out the hard way. I found a 1/4" wire brush on Amazon which I used to remove the anodizing from the inside of the shaft to make better electrical contact with the insert. It seems to work pretty well. I don't have a 3D printer so I just connected the shafts so some 3/4" aluminum square stock I found at Home Depot which seemed to work well. I used some 8-32 screws which go through the boom. It took 2 36" pieces of square stock to make the boom. I joined the boom pieces with a piece of scrap 1/2" copper pipe which fits nicely in the square stock. It's not as light as I'd like but it fits nicely into a 27" tripod bag for portable operation. I'm going to try something similar using wood instead of 3D-printed plastic for the element-to-boom connections. Thanks for the video and ideas.
See my other comments under Chris Sewell, but also I'll add here: More aluminum arrow info: The four digit numbers are the sizes, ex: 2213, etc. The first two numbers tell you the diameter and the second two numbers tell you the thickness of the metal. A 2117 is smaller than a 2213, but it also has a thicker wall. Stiffness is a function of diameter, and so is bandwidth. Also these numbers are how you buy the right sizes of inserts and tips and nocks. Enjoy.
That is a great build. The size is perfect for stashing out of the way when not in use, and definitely ultra-portable. Just a thought - that could be the new, highly sought-after "KM4ACK 2M Yagi Kit". Great video, thanks!
What if you used brazing to attach the inserts to the aluminum arrows? it's basically soldering and with silver brazing rod it would make a great electrical connection.
Some great ideas/suggestions already! My 2 cents...I would use a glob of fletch-tite or thick/gel CA glue .5" inside shaft. Then push insert in and use hex/coax crimper of appropriate size for mechanical stability then stand vertical till glue cures. Electrical connection should be ideally made on the face end of the shaft like where you cut to length and the inside lip of the insert, assuming you can square and match both surfaces to minimize gaps. Remember skin effect is your friend here. Make sure you use brass inserts rather than aluminum to greatly reduce corrosion on the aluminum from interaction with the steel threads. Nice build Sir!
I will try the glue you suggest :-) I just had the thought yesterday to try coax crimpers. Not sure why I didn't think of this before the video. Works like a champ and give exactly the desired results. No problems with continuity on the few tests that I have done so far. I think this will be a winning combination! Thanks for the tip on the glue.
Try a prick or starter punch and lightly tap a dimple on the outside of the shaft into the insert in a few spots around the shaft....it's not like you need the shaft to fly straight. The dimpling should give you a quasi crimp. This also works for standard nuts to prevent them from backing off a screw or bolt when you don't have a nylock nut.
I like it. I'll probably do something similar in future. For 3D modeling I use Free Cad. It's a parametric package so you can get all the measurements accurate. Bit of a learning curve, but works very good at this point, for the most part. Also, it's Free. Works on Linux and Winders. :) (probably works on that 'other' system too.) If I find a conductive epoxy, I'll come back and post it. I also like the heat it and let it shrink on that some one else posted.
Have made a ton of arrows for actual archery use, though I use carbon fiber arrow shafts, not aluminum... the inserts are typically glued in with a couple of drops of CA glue. That's strong enough to keep them in when shooting them at nearly 200 mph from a compound bow and surviving the impact at the other end!
Adam used a crimper to crimp-in his threaded inserts into the arrow shafts. I am not sure what kind of crimper, etc, but check with him (if he hasn't commented here yet) - I've been wanting to build something like this myself so I'd be interested to see what you come up with.
I have been researching portable yagi antennas like this. I haven’t asked him but I thought Adam,K6ARK used a bnc crimp tool. I thought I would try a silver epoxy, as it’s supposed to be electrically conductive. Also in archery I use hot glue for my arrows used with my compound bow, but that would prevent continuity
Fantastic project, Jason. This would be perfect for 2m SSB and FM simplex. Your 6 oz. build speaks to my man-portable soul. I am wondering if Loctite would work for your application? I would to love try this for mountain topping once they're available. 73 de KT1RUN
Great build! I have been using my arrow antenna (vhf elements only) on several SOTA activations where I couldn’t get any contacts with just my HT whip. Problem is, it’s a bit big and a bit heavy - looking at a DIY builds and your 3D element brackets are great! Is it a file you share? Cheers
Great video. Glad I found your channel, new Subscriber. A couple of thoughts. Aluminum arrow shafts are usually an alloy, very stiff and brittle so a crimp or dimple (good ideas, by the way) might tend to crack these shafts. Two important things, 1 - need to keep the internal ridges on the inserts clean and 2 - need to maintain electrical conductivity between the insert and the shaft. check out a local sporting goods shop, preferably one that has a good archery section. with knowledgeable personnel, big boxes usually don't really have these type if employees. Easton does offer a couple of adhesives, one a 24 hour epoxy and another quicker setting adhesive. typically, these are applied to the entire insert possibly eliminating conductivity. Might try just to apply the adhesive to about 1/4 to 1/3 of the tip end and carefully insert it. Might be a good solution. Have a lot of archer friends and maybe able to score some of there old aluminum shafts.
Jason, you might want to try to some small hex head screws to tap an eighth of inch to one half inch and stake the screw head. I compare it to staking the parts on a gun. Patrick
Jason, there was something else that I thought of. If you have something similar to what buddipole has, “Knurled Whip Sleeve” but with outside threads on one end and the inside threaded on the sleeve on the other end. Then you can have the outside end on the arrow shaft that will attach to boom threaded in addition to what I previously recommended. You are ready for portable operations as mentioned in your video. Patrick K6PFG.
Jason, what size arrows? i'm still trying to build this and the details here are not given. I'm looking at arrow shafts online and i'm seeing sizes such as 1214, 1416, 1516, etc.
Edit: Jason, if I'm not mistaken, you can remove all 3d printed items except for the director. If you drill through the Al shaft the threaded rod should be a smaller diameter than your boom. Then you could just screw them directly and just use your 3d printed plastic just for the director. I thought Adam K6ARK had a video showing something similar. There are a couple more guys out there with videos too. Either way, I'm in agreement that this should be in your store! What's that link again? Edit: KK6USY was the guy. This is the video. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-iv6CKQwnRtQ.html K6ARKs video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-a4XIgYD-d1k.html
Hey Jason! I did a similar Yagi but instead of arrows I cut some hard aluminum tubing I bought from a metal distributor in Brazil and threaded one end with a 1/8 tap. For the boom I used a PVC pipe, but using aluminum as you did would make it much lighter! Great build
@@KM4ACK you defiantly have my attention with this project. Thinking about the threaded inserts, could you solder them onto the arrow material like copper water pipes get "sweatted" together? Best of luck and looking forward to the updates!
It look like the mobilinkd 2 has been dropped. Not showing up on the website. You could try reaching out to the developer in this forum and see if he has plans to bring it back. It could just be a parts shortage. Not sure. groups.io/g/mobilinkd/topics
