3D Print Your Next Antenna

Building antennas is a time-honored ham radio tradition. Shortwave antennas tend to be bulky but at VHF frequencies the antenna sizes are pretty manageable. [Fjkaan’s] 2 meter quadrifilar helicoidal antenna is a good example and the structure for it can be created with 3D printing combined with electrical conduit.

Many people, including [G4ILO] use PVC pipe for the structure, and that design inspired [Fjkaan]. Despite being a bit less substantial, the conduit seems to work well and it is easy to cut. The helical design is common for satellite work owing to its circular polarization and omnidirectional pattern.

A quadrifilar helicoidal antenna is really two antennas in one, with a phase difference of 90 degrees between the two. There are several ways this can be accomplished, but in practice, most of these antennas use different loop sizes for the two antennas. One loop will be a bit larger than the frequency of interest, and thus will be inductive. The other loop will be a little smaller, and therefore will exhibit capacitive reactance at the center frequency.

Even though the antennas are both reactive, in parallel, the reactances cancel leaving a nice resistive load to match the radio. The feed at the top, however, needs to balance through some form of balun or choke.

We’ve seen these antennas do great things before. If you need a satellite receiving primer, we saw a good one last year.

40 thoughts on “3D Print Your Next Antenna

  1. “Even though the antennas are both reactive, in parallel, the reactances cancel leaving a nice resistive load to match the radio”

    But don’t you need to use a base plate of pre-famulated amulite surmounted by a malleable logarithmic casing in such a way that the two spurving bearings are in a direct line with the panametric fan. ???

    1. You may be confusing this with a turbo-encabulator. The short answer is, no, you don’t. But now that I’m trying to answer in the spirit in which the question was asked, I realize that [Al Williams] explains it way more translucently than I ever could. Read it again, and be both enlightened and irradiated.

      1. How? Well, we bolster twelve husk nuts to each girldle-jerry, while flex tandems press a task apparatus of ten vertically composited patch-hamplers. Then, pin-flam-fastened pan traps at both maiden-apexes of the jim-joist.

  2. Solder paste contains fine beads of solder. Can you get 3D printer filament containing fine beads of ferrite?
    Especially at lower frequencies, the ability to create antenna supports that include ferrite could significantly impact overall size.

    1. There are “high” permeability magnetic filaments, which people have tried (with limited success) to make motors, which are essentially iron powder (or maybe iron oxide powder) filled thermoplastic, which really ought to be characterized for this sort of application. Not an actual ferrite, but might have interesting properties anyway. Also, there was an article here on printing with “filament” made from old VHS tapes that could also be helpful: https://hackaday.com/2020/12/16/3d-printing-with-vhs-tape-filament/

      Of course, neither of these is likely to be able to handle much power dissipation, so it may take larger cores than you’re used to.

  3. How is it NOT a hack? It’s a circular polarized omnidirectional VHF antenna made from bits of plastic and wire (possibly of the baling variety). The fact that it’s not the first circular polarized VHF antenna so made does not invalidate its hackerosity.

    More importantly, though, it demonstrates how to make your own variation on tinkertoys.

    1. Jim and e,
      Your comments illustrate how degraded online forums have become, and how ignorant society in general has become, even in a sector you would expect people to be of “higher than average” intelligence, i.e. the tech sector, albeit hobby-level on this site.
      Hacking has always meant gaining unauthorized access to a computerized (i.e. electronic) system in order to make it do something it isn’t supposed to do, or wasn’t design to do…
      And you guys think that printing yet another antenna housing in world of millions (tens of millions?) of antenna housings is somehow a “hack”.
      Very sad to watch even the hobby-level sector de-evolve into a sea of mimics all copying someone else’s work (someone who did something that has been done thousands if not millions of times before) and say “look! I hacked it!”.
      This causes me to completely lose faith in the tech sector in general. People are becoming dumber, more ignorant, when they should be doing the opposite.
      If you haven’t watched the movie “idiocracy”, you should. We are headed that direction, and quickly.
      You guys are literally calling an antenna housing a “hack”!!!

      1. Your comments illustrate how degraded online forums have become
        Your arrogance illustrates that clearly.

        Hacking has always meant gaining unauthorized access to a computerized
        No it hasn’t.

        To quote ESR, who is most-certainly more qualified to define “hacker” than anybody with “based” in their name: “Hackers solve problems and build things.” (If you don’t know who ESR is, all the sadder.)

        People are becoming dumber, more ignorant

        1. Gamma, your comment illustrates exactly what I am saying. Anyone born more than 20 years ago should know what hacking means. Now, all these mimics (I am guessing you are one) come along and say “hey, I want to be a hacker too, but it’s too much work – Can we redefine that word within our little group? That would make me feel super important without acually accomplishing anything”. Thanks for proving my point there.

          Calling me arrogant because I hold to traditional standards for an industry and terminology is just silly. In the words of the sniffer-in-chief, “Come on, man!”

          Not sure why “based” triggered you, please do explain if you care to xD

          1. Based Whale, I think both meanings of the word come from the same place. “Hacking” in the 1960s meant taking stuff apart to figure out how it worked. Which applies to security systems, locks, telephone systems (both “phone phreaking” and wiretapping), and home electronics with “no user serviceable parts inside”. At this point, though, what’s important to the immediate discussion is that I’m pretty sure Hackaday, while it may originally been mainly about breaking into systems without authorization, is no longer that exclusive. It will do you no good to fight the tide, since a lot of people who don’t have any interest in breaking into things are here for other dimensions of hacking. The more fundamental characteristic of all hacking, as I see it, is learning what goes on underneath the surface, and being privy to the secrets that are not for ordinary people to know. Thus, RF hacking has it’s own appeal, when wireless communications is something you buy or pay for as a subscription service This, by the way, is how Autodesk gets it wrong, with trying to sell us subscriptions to Fusion 360 and Eagle, which is an affront to anyone who learns skills so they DON’T have to pay for them, so by all MEANS we will work around their “security”, but I digress. There is an element of pride to completing an RF communication that did not go through the regular paid-for routes, through something you “hacked” together out of parts, just as there is to opening a lock using your own wits and one or two tools you made yourself.

        2. And while I’m at it, I do see what you object to – people are calling themselves “hackers” because they found the cheat codes for a game online, or downloaded an STL file to 3d print something they found on Thingiverse. Let me be clear, these are wannabees, and they don’t count. Any time I see something cool online, and people are asking for the STL files, it bugs me. It’s right in front of you – model it yourself! Make it your own – you HAVE access to CAD tools.

          But tell me something honestly: did you never try a hack you read about, that someone else did? Yes, hacking is about working things out for yourself, but that doesn’t mean you cant take tips from other people, and from what you see around you. The article we’ve gone so far off track with here, appealed to me not because I could download some fittings to make an antenna, but because I see how simple it can be to make the necessary fittings to connect tubing together at arbitrary angles, and now I know I could make models to use in other applications with similar needs. I mean, as silly as this is, I was thinking that it would be difficult to print these without supports, because the bottom half when printing would be a curved surface that’s all overhang. But I looked at the picture and said, “duh, the cross section is octagonal, so you only need to be able to print a 45 degree overhang.” So did I cheat, or am I smarter now for it?

        3. @Jim
          I think we are on the same page here.
          Let me give you an idea of where my opinions on this come from and why I have no respect for the mimic community: Many years ago, I did publish some “hacks” and other projects that I did. Modified some things to do something they were not meant to, compromised several systems to gain greater/very desirable functionality, and a few useful projects I designed from scratch.
          Because I did not provide step by step instructions, PCB layouts, schematics, etc, I received mostly negative feedback once the mimic crowd realized I was not going to give them my work, and instead was only going to give the necessary hints to figure it out themselves, and learn something. I was disgusted by this. This was when I realized that a majority of the mimic/maker community was comprised of people who like to talk about cool stuff, copy cool stuff, but who have no real passion nor drive to really understand it and take it further.
          I do however acknowledge that there are many individuals who do take it further, and many actual engineers contributing things, it’s just this mass of mimics that gets me. Publishing a project in its entirety, including all plans, source, etc, “feeds” these “fish”, and I think it’s better to just not feed them so that maybe they cand find the drive to feed themselves.
          I see a major dilution in the tech industry in the USA, and it disheartens me. Too many kids nowadays have no idea what it means to actually have a passion for something, and have no drive to push their interests to the limits. I see “half-assers” everywhere I look nowadays. It’s pathetic.

      2. Well, thee’s your problem right there. Your definition of “hack” differs from the rest of us. What you describe is ONE kind of hacking. The other part is making things you can’t buy, or things that buying costs too much. You see it as the “degradation” of the community, while many, many others find value in it. I don’t personally see any value in the kind of hacking you’re talking about, but I don’t complain when I see articles about that; I just skip them. It’s easy, and costs me very little time.

        1. Jim,
          If you’ve been around a while, the definiton of “hacking” should be quite clear to you. Hacking definitely is not doing something that has been done a thousand times over (that is what we call mimic) and simply building an antenna, which has been done, I dunno, hundreds of millions of times over – Using a 3D printer, which prints plastic, which is what it is intended to do… See what I am saying? There is no hacking here. It’s a cool project. Not a “hack”. We do not get to redefine the meaning of a word just because it makes us feel more important or special or more capable (when in fact we are no more capable with or without the redefinition).
          This is the same as someone who wants to be a pilot, but isn’t willing to put in the hard work to become one, so they redefine “pilot” to be someone who looks at planes… Or makes plastic ones and throws them though the air… Or whatever.

        2. @Based Whale, et.al.,
          I don’t see anyone claiming, “look! I hacked it!” However, I understand where you’re coming from completely. For instance, seems to me there is a conspiracy to re-define the American English language just like the curricula in school to create more dependents and less independents.

          Thinking the causation is the governments armed robbing capabilities to levy taxes, fines and fees like there is absolutely not recourse for ill and/or wrongful behaviors due to the situation of the J.D.’s turning into Roman Tribunals literally. Furthermore, unlike like other corporations… they don’t file bankruptcies much at all. They just compound and conceal more, obstruct justice and desensitize the masses to be more complicit in ill deviant behavior and dependent on the gooberment funds.

          Would be nice if this was “crackaday” or “keygenaday” or some other former “hacking” firmware or hardware that is a proprietary inclusive only media outlet.

          Let’s not get emotionally magnified however, as I had to learn with cognitive behavioral therapy and alternate thoughts to my valid thoughts and others invalid thoughts typically, since I started to realize how being a leader is like when not dealing with even USAF Sgt. Dad who wasn’t perfect either. Was reminded why I was OK with Directing and not with Supervising straight out of Tech.

          The pilot statement very clearly reminded me of how the wanna-be’s in those careers are even changing in their ways by having not qualified force missions with roles of pilots pilot drones, monkey proof pilot compensation avionics and controls for pilots in aircraft (I think all other than USAF/CIA) and well… those not even qualified as pilots who’ve piloted complain about the gangster gamer juvenile and more dangerous latest rounds of head count recruits filling roles.

          I recall an attorney friend of mine decades ago noting a gal I knew claiming she was an accountant… and he reminded me she’s only a book keeper. I was stuck on she’s not an accountant, no CPA, CMA or CIA credentials.

          Some get entitled to titles they don’t want. I didn’t mind being called “Nerd,” “Grandpa” and “Dr” in my 20’s… though wasn’t what I was going for at the time.

          Many go through life delusional and unfortunately if they influence others…, leading others to be more diluted and degraded more. Just don’t be that.

          Great to read you’re standing yours and others ground.

      3. “Hacking has always meant gaining unauthorized access to a computerized (i.e. electronic) system in order to make it do something it isn’t supposed to do, or wasn’t design to do…”

        Yeah, no, this is completely false.

        Hacking originally was the term used for software engineering, before the term ‘software engineering’ was a thing.

        Only later was the term applied to the subversion of systems, both hardware and software based via unauthorised methods.

        1. Bob,
          While I do agree with you that early on, it was loosely used as a term for busting out some code, it was not formally defined as such, and used as a slang term. IMO, its official definition was quickly formalized as the result of actual hacking, as we knew (and still know) it, and was defined as such for decades. Many movies were made about this. Now, we have this maker/mimic community that has emerged in the past decade or so who like to copy projects and declare accomplishment, and it is this community that has attemted to hijack and derail the use of this word. I have encountered hundreds of these people, all who use this word to describe their mimic projects, as a way of establishing some sort of credibility with their peers. This is not the real world, and I will not accept a bunch of hacks (not hackers) who think they can redefine the term instead of learning how to be a real hacker.
          It’s the same concept as these kids who cheat their way through engineering programs, devaluing the degrees of the hard working peers around them. Not cool. I can not take the maker/mimic community seriously, because the majority of their members continue to be discretely separate from the professional level engineering community, and for good reason – Because the vast majority of them are not willing to put in the hard work to become actual engineers or hackers.

        2. > Now, we have this maker/mimic community that has emerged in the past decade or so who like to copy projects and declare accomplishment, and it is this community that has attempted to hijack and derail the use of this word.

          While the maker/mimic community is using the term, it was used that way for decades prior to the modern emergence of that community in its form. (Seems that for a lot of the ‘maker’ community, I often find myself feeling a lot of derision for their claims & results, or both, like grasping to find patience & praise for a child upon making their first clay ashtray that looks like a flattened and truncated cousin to an octopus…)

          Going several decades back, parallel to the earlier days of software, I’d seen it & used it two ways:
          – a hack – using or modifying something intended for another purpose to manage to achieve a ‘hack job’, that while wasn’t the best quality outcome, you managed to achieve the task with what you had or could make on hand
          – a hack – same as the first, only the outcome is of same or similar quality as the proper tool or process, and/or the time/effort/cost/skill to achieve it is meaningfully less – with the resulting amusement, pride & bragging rights
          Plus ‘hacker’ and ‘hacking’ used in regard to the above.

          Two examples :
          Using early epoxy to fix a hole in an airplane float so it could take off and get back to base to get the proper repair.
          Hockey sticks & fibre-stranded packing tape to wrap a wing strut to fly a ski-plane back to base.
          (First by my father, second by a family friend)

        3. – continued

          Using something one has on hand (3D printer) to be able to produce custom dimension components to be able to DIY an antenna that would usually be purchased, is certainly a ‘hack’. And has the benefits of a relatively sophisticated tool and a relatively precise and sophisticated outcome.

          To me, although working in IT going into my fifth decade, it is re-purposing by movies & news to use it as what we call “computer hacker or hacking”. It annoys me to see young people only aware of the ‘modern’ usage of the term.

          I wonder how much of hacking being adopted to computer coding, came from patched, ‘jury-rigged’, or hacked-together code… Particularly when modifying ‘official’ code to ‘hack’ a system.

          The first I saw it used with coding was to refer to ‘hack code’: poorly written code that may not or may have somehow managed to achieve the desired result. A hacker was someone who really didn’t know how to code properly, with typically poor results. Profs commenting: “he’s just a hack” or “hacker”.

          Or course we weren’t consulting dictionaries on how to properly use the terms, we just used them as we understood them. I guess a hack, per se.

      4. I recall reading late last century the inspiring book “Hackers, heroes of the computer revolution”, that was written by Steven Levy and published in 1984.

        And yeah, the good book doth verily sayeth unto us:

        “The Tech Model Railroad Club (TMRC) is a club at MIT that built sophisticated railroad and train models. The members were among the first hackers. Key figures of the club were Peter Samson, Alan Kotok, Jack Dennis, and Bob Saunders. The club was composed of two groups, those who were interested in the modeling and landscaping, and those who comprised the Signals and Power Subcommittee and created the circuits that enable the trains to run. The latter would be among the ones who popularized the term hacker among many other slang terms, and who eventually moved on to computers and computer programming.”

        To quote the wise old elf: “Bodge, yes, that’s a technical term we use in the building industry”, similarly, “Hacking” has more to do with clever, functional solutions than unauthorised computer entry, which many old school hackers have preferred to term “cracking”.

        I still stand be my conclusion that the linked antenna is a hack, because he found a solution that will mostly work using little more than a spool of filament and coax, but it is arguably less robust than using shop bought bits.

      5. I call troll!

        Whale boy is looking at all the long winded well thought out but emotionally charged replies and he knows he’s got you! He probably doesn’t even believe his own writings but he is laughing his ass off at your expense!

        Don’t feed the trolls!

  4. One thing to keep in mind, this is a thermo-plastic. I printed an antenna frame for a lightning detector magnetic antenna https://map.blitzortung.org/#0.88/0/6.8 and put it up in the attic. After a couple of weeks, the antenna was showing some issues, and I popped back up to the attic to check it out. The heat in the attic had softened the PETG to the point that the mount deformed and the antenna elements were no longer perpendicular.

    1. After PETG, Nylon is the next material I want to be able to master 3D printing.

      Stryrene and Delrin would be nice for some signals designs… though yeah… environmental conditions requirements.

      Thinking the above two materials will be after the Nylon… at least I hope.

  5. There are a lot of definitions for the word hack. I believe the way it is used here is to assemble something in a less-than-professional manner, possibly out of items which weren’t intended to be used in that way. This is most similar to the 1B definition below.

    Definition of hack (Entry 1 of 7)
    transitive verb

    1a: to cut or sever with repeated irregular or unskillful blows
    b: to cut or shape by or as if by crude or ruthless strokes
    hacking out new election districts
    c: ANNOY, VEX —often used with off
    He gets really hacked off when people cheat.
    2: to clear or make by or as if by cutting away vegetation
    hacked his way through the brush
    3ainformal : to manage successfully
    just couldn’t hack the new job
    binformal : TOLERATE
    I can’t hack all this noise
    4: to gain illegal access to (a computer network, system, etc.)
    In the last decade they have hacked computer networks in Estonia, Ukraine, Poland, Germany, France, and Bulgaria—often stealing data.
    — The New York Times
    … perhaps I would have become one of those lost souls wandering the basement of MIT playing with computers and hacking the telephone network.
    — Lee Smolin

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