How to construct a multi-band dipole using speaker wire 30

The workbenchI decided to build a multi-band dipole antenna as soon as i found out our new flat had loft access. After previously being constrained to a magnetic loop strung up in front of our living room window this was very exciting. In addition to this i even acquired an extra bedroom in which i could convert into a shack.

Dipoles are relatively easy to construct and are pretty cheap compared to commercially available antennas and in some instances a simple dipole can outperform other ‘compromise antennas’. I estimate that this dipole cost me a grand total of £35 (£20 for the speaker wire itself), not bad going for a multi-band HF antenna! I obtained all the components from eBay.

It’ s been working really well so far (used up to 50w – my current license restriction) and i’m very happy with its performance. I’ve only used it for PSK31 so far but i have had many QSOs on it including JA5BVO (Japan), OX3DB (Greenland), N1HNY (U.S) and PY2TWI (Brazil). Here’s a screenshot of the PSK31 signals that i’ve been putting out:

PSK Reporter


Multi-band dipole! How does that work?

My initial question about a multi-band dipole was how could this magical thing work? How is the correct dipole length selected for the frequency being transmitted through the coax? It turns out there’s no magic, the correct dipole wire is selected automatically based on the one that offers the least resistance. This is how you can feed all the dipole wires at once with a single coax feed and only have the correct segment radiate the signal.

I wanted to build a simple multi-band dipole that would cover the major HF frequencies that i’m interested in. I quickly had to forget about the 80m and 160m bands due to the length of a half wave dipole (40 meters and 80 meters respectively) and a distinct lack of loft space. I chose the following HF bands:

  • 40m
  • 30m (data band)
  • 20m
  • 17m
  • 15m

Dipole Components

All of the dipole components were purchased from eBay and included:

  • 100m of speaker wire (2 strands)
  • Dipole center (you can make your own, but this makes life easier!)
  • PL-259 Male Connectors
  • PL-259 Female Couplers (for joining two PL-259 connectors)

Speaker wire is formed of two wires, one made from stranded copper and the other one steel. For the antenna i was only interested in the stranded copper wire, so i needed to separate these from each of the lengths i had cut. This is quite easy as the two lengths are insulated separately and can be split easily as a result.

The one problem i had with the speaker wire was that the outer insulation seemed to be greased, requiring me to put the wire on top of a plastic sheet to stop the carpet from being stained. The XYL was out during this procedure and never suspected a thing!

Building the ugly 1:1 choke balun

I also made an ‘ugly balun’ to match the unbalanced coax feedline to the balanced antenna. The purpose of this to help eliminate RF currents from flowing on the outside of the coax, this ultimately ensures that the dipole is radiating the RF and not the feedline.

See my ugly balun construction post for a full step by step guide of its construction.

I used the following components to construct the balun:

  • 22 feet of RG8 coax
  • Empty 2 litre drinks bottle (to act as a former to wrap the coax around)
  • 2x PL-259 connectors
  • Sellotape

The final ugly balun, it is indeed very ugly (but functional and cheap!);

Ugly Balun


Constructing the dipole

The following section outlines step by step how i constructed the multi-band dipole.

Preparing the Speaker Wire

First of all i cut the speaker wire in to segments, corresponding to the bands i was interested in, the basic premise being to use a length of wire half as long as the band wavelength you wish to use. Here’s the lengths i used for each band:

  • 40m – 20.09 metres of wire
  • 30m – 14.12 meters of wire
  • 20m – 10.06 meters of wire
  • 17m – 7.88 meters of wire
  • 15m – 6.72 meters of wire

To calculate the length of wire for other frequencies you can use this formula:

Total length (in meters) = 142.65/ƒ

For example if we wanted to add the 12m band (24.940MHz), we’d do the following:

Total length (in meters) = 142.65/24.940

Total length (in meters) = 5.72 meters (rounded up to two decimal places)

Once you have your length of wire for your desired band you will need to cut the wire in half again for (one for each side of the dipole).

You can of course trim the lengths at a later date to get the perfect SWR, but i found the lengths above to be about right.

Soldering the dipole center

At this point we have a whole bunch of wires and a dipole center. I found five wires was about the maximum i could thread onto each center tag (ideally i wanted to add 6m to the antenna but had to forget this idea). The next step was to solder the wires to their corresponding solder tag, i found it easier to first thread each wire through and then wrap the wire around the end tag, once i had done this for all five wires i soldered the whole lot in one go:

Soldering one dipole end

I then repeated this for the other side of the dipole. I wanted to keep things neat so i also secured cable ties around each side. Here’s what i ended up with:

T-Connector Feed Point

We now have the completed multi-band dipole, so lets get it strung up…

Mounting the Dipole

I mounted the antenna in my loft, so i didn’t need to worry about weatherproofing it. You want to mount the center feed point as high up as possible in the apex of the loft to keep it away from electrical wiring and copper boiler tanks!

You also want to make sure that each wire comes off quite separately from the others at the feed point:

2013-09-15 11.40.28


I used a staple gun to support the wires throughout the loft.

Ugly Balun in Loft

Let the final 4 inches of of the dipole wires hang free away from the wood. This is for reasons of safety and stops the dipole arcing to the woodwork:

2013-09-15 11.41.32

I found that my loft wasn’t big enough to have the 40m and 30m wires out in a straight line, to get around this i zig-zagged them along the loft:
2013-09-15 14.03.37

The End Result

The final result of my construction of this antenna is that it outperforms my other expensive commercially available antennas! The end product is cheap and i’ve had hundreds of QSO’s on it so far (using up to 50w) including some nice DX. The SWR always seems to be very low across the bands and the reflected power rarely exceeds 3-4 watts (assuming 50w from transceiver). All in all i’m very happy with it and there is a massive sense of achievement when you make contacts from an antenna you made yourself.

This marks the start of my interest in antenna construction and i’m sure this won’t be me last one.

30 thoughts on “How to construct a multi-band dipole using speaker wire

  1. Reply Stephen Dec 31,2013 19:14

    Made this and installed today although not pinned up the 20m/40m wires yet. I added wires for 10,12,15,17,20 and 40m. Didn’t solder just wrapped around the screws and used a washer to keep them all down. Cable tied all cables to the centre piece. 1st QSO on 17m in Bulgaria (from UK) so is working and ATU tuning well on all bands. Thanks for the guide.

    • Reply James Stevens Jan 1,2014 18:39

      Glad it worked for you Stephen, its certainly done well for me making a bunch of DX contacts during 2013 🙂

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  4. Reply Gary Feb 25,2014 16:36

    Do you still use an antenna tuner with this?
    I’ve been looking to build something like this myself. Thanks for the write-up.

    • Reply James Stevens Feb 26,2014 11:33

      Hi Gary,

      I don’t use a turner for this, not at least for the bands i’ve cut the dipoles for. You may need to do some fine trimming of the lengths to achieve a low (SWR less than 1:5) and try (if possible) to keep the dipoles for each band as far apart as possible, i noticed some interaction when i trimmed one and moved the position of it, where it would affect the SWR of another band dipole.

      Hope this helps and go for it, very satisfying to build your own antenna!

      73s, James (M0JCQ)

  5. Reply Alan May 23,2014 14:19

    Not sure what I’ve done wrong here. I’ve followed the instructions and I can get it to tune well on everything other than 20 and 40m. The lower end of 40 is completely unusable and the upper is very poor. I guess it would indicate a length issue but I was very careful in my measurements!

    • Reply Alan May 23,2014 23:26

      Turns out it needed to be longer, a fair bit longer. Some chocolate box connectors and some extra wire together with a bit of maths saved the day. 1.1 SWR on almost all bands now. First contact North Italy on 5w 🙂

  6. Reply David Smith Oct 28,2015 22:20


    Excellent thinking and I am actually going to give it a bash over the next few days.

    Thanks and have a great night

  7. Reply Ian Chard Jul 30,2016 19:32

    Thanks so much for this. I’m planning to give this a go in the next few weeks. However, my roof has metal flashing along the apex. Do you think I should run the wire away from the apex to avoid being close and parallel to it?

    • Reply James Stevens Aug 21,2016 18:17

      Hi Ian, I would certainly try and keep the wire away from the apex. You may find the SWR affected quite significantly by the proximity to the wire.

      I certainly noticed interaction between the different wire elements when I decided to reconfigure their positions after trimming!

      73, James M0JCQ

  8. Reply thomas morgan ka7fff Jun 15,2018 22:53

    my apologies,I’m unfamiliar with this site!! I’m working on a project of my own!! it’s a directional antenna I’ve bought on eBay!! it handles the vhf / uhf spectrum!! but do I need a balun for voice calls on repeaters!?

    • Reply James Stevens Jul 9,2018 10:42

      Hello Thomas,

      I would advise using a balun with every antenna, at least to stop the power coming back down the coax outer shielding into the shack. It doesn’t need to be complicated, you can easily wind a few turns of coax to make an “ugly balun” , or wind a few turns of coax through a ferrite ring. The number of turns depends on the frequency you intend to use.

      Whether you really need to do this to make a few contacts? I’d say you don’t (I’ve done it many times while portable!), you’ll still make plenty of contacts ok without this, but you might be getting RF coming back down the coax causing RFI issues in the shack and the antenna may not radiate exactly how it was intended.

      73 James M0JCQ

  9. Reply Dan W Oct 10,2018 19:38

    Amazing work! Just a quick question – what grade speaker wire did you use? I’m assuming its not 79 strand? I’ve found some good 42 strand in a 100m length, but wanted to double check what you’d used, thanks!

    • Reply James Stevens Oct 11,2018 11:20

      Hi Dan,

      It definitely wasn’t 79 strands, it was quite thin and probably less than 42 I’d say, probably half that even! Anything will work but overall length and bandwidth may well be different.

      Good luck!

      73 James M0JCQ

      • Reply Dan W Nov 9,2018 21:30

        Got the wire, made the balun… but another issue has cropped up. My shack is 1st floor, I then remembered that your article stated you are first floor also – so I figured you’d be in the same boat, that boat… the grounding issue. What do you do for an RF/Case ground on your rig? Do you bother? Or have you run a traditional earth down to a ground spike?


        • Reply James Stevens Nov 22,2018 11:39

          Hello Dan,

          We were on the second floor at that point, with no possibility of a (good) ground). There was nothing in place other than the rig case being connected to the power adapter (common to both my ICOM 7100 and 7300).

          I’d be much more concerned with an earth spike if I was intending to run power, but at that time I was mostly running a maximum of 50 watts.

          73 James M0JCQ

          • Reply Dan W Nov 24,2018 12:00

            James – many thanks for your advice sir, the more I read up on dipoles in general, the more I came to the conclusion that the earth was probably largely irrelevant. The antenna is working well so far, with 2m-17m runs on, adding 20 and 40m today 🙂

          • Reply James Stevens Nov 25,2018 12:13

            Glad to hear it Dan! I’d be much more concerned with using an earth with QRO power. But with a balanced antenna I’ve not found the need.

            A simple choke balun was needed to prevent RFI in the shack (laptop kept restarting on TX) but nothing more.


  10. Reply Greg Norris Dec 2,2018 13:25

    I’m having a go at your multiband dipole & ugly balun for a receive only sdrplay unit I’ve just installed. For a trial run outside (over our boundary frence) I’m wondering if there’s any reason why the wires for the 4 bands I’n covering can’t be taped together rather than separated out??? Any thoughts on this? My longest wires are 2x 20m and I can just get them at full stretch along our side fence.
    Any opinions welcome

    • Reply James Stevens Dec 4,2018 13:40

      This is an interesting question Greg, but not one I know the answer to. Certainly this wouldn’t work for TX, but RX only you may well be ok, if the wires are insulated from each other.

      There’s certainly interaction on TX between the elements, especially if they’re close together, but for RX I don’t know if you’d notice much performance impact.

      73 James M0JCQ

      • Reply Greg Norris Dec 4,2018 16:12

        That’s what I’d concluded too – we’ll soon see as I’m part way installed, but not quite finished.
        More news when I have it !!

  11. Reply Dave Beard Jan 24,2019 12:16

    Hi James

    I’m just about to do my Foundation exam and like the look of this aerial, my intention is to mount it along the front of my house, is there any reason why you didn’t use separate solder tags for each wire, I guess it’s also like a fan dipole.

    • Reply James Stevens Jan 24,2019 12:59

      Hi Dave,

      No real reason, other than saving solder tags. Both approaches work well!

      Good luck with your foundation exam.

      73 James M0JCQ

  12. Reply Kevin Feb 20,2019 20:07

    Good job.

    I remember putting one of these up in the attic in our old house. I was an M6 then. It worked a treat. I added traps to the 20m to get a short 40m. It was made from all sorts of wire. Ethernet stripped mains and speaker wire.

    They a lot of fun to make.

    73 Kevin MOLKJ

  13. Reply Dale Apr 29,2020 13:35

    Hi would this system work in a loft that had lightning protection installed on the outside above it,
    Every house in our area is required to have lightning protection
    Great project and super instructions

    • Reply James Stevens Apr 30,2020 09:10

      Hi Dale,

      I’m not sure of the nature of the lightening protection you have installed, any nearby metal could possibly cause the dipole to detune off the calculated frequency. I would imagine short of the protection creating a Faraday cage around your roof, you’d still be able to get a signal out with the dipole!

      73 James M0JCQ

  14. Reply Bob May 6,2020 22:06

    Never heard of speaker wire being one copper / one steel. Normally one is copper colored, the other is tin plated copper – may look like steel but is just tin plated copper. Did you check the ‘steel’ wire with a magnet. I’ll bet you dollars to donuts it was just tin plated copper. Please let me know.

  15. Reply James Oct 14,2020 23:49

    If you don’t mind me asking what is the size of your loft ? i have a diamond x200 installed in the middle of loft, just wonder if it would affect it having it them set up near each other.

    • Reply James Stevens Oct 15,2020 11:04

      I’m no longer at the same property James, but it was not very big, maybe 10m long and 5m wide.

      I’d imagine having the Diamond in the middle would affect the tuning of a fan dipole, but that shouldn’t be a problem as long as you trim it with the X200 in place (and don’t move it later!).

      Interaction between the dipole elements was significant, so I imagine having the X200 so close will result in the same.

      73 and good luck,
      James M0JCQ

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