Link Coupling Antenna Tuner Wordless Workshop

Remember “Wordless Workshop” in Popular Science? [Roy Doty] illustrated a household problem and the solution for it cobbled up in the main character’s garage workshop. We wonder what [Roy] would have done with YouTube? Maybe something like the video from [VE2TAE] and [VE2AEV] showing their link coupling antenna tuning build. You can watch the video after the break, and if you aren’t a fan of Jazz, you can mute the volume.

Like [Doty’s] cartoons, the video presumes you are going to have your own idea about dimensions and component values to fit your needs. But the construction is beautiful in its own right. The tubing wound into giant coils is impressive and brings back memories of the old days. However, the construction of the variable capacitors really got us excited. Big air variable caps may be hard to find, but the video makes them look easy to make.

A couple of nice looking knobs and panel meters make for a great looking tuner. With that spacing, we imagine it would handle full legal power without any difficulty at all. If you want to learn more about this type of tuner, [VK1OD] had a great page about it which seems to be defunct now. But the Internet Archive comes to our rescue, as usual.

The design is quite old, so even a 1934 copy of “Radio” can explain it (look on page 6). If you want to see a more wordy example of making variable capacitors — although they are smaller, the same principles apply — [N4DFP] has a good write up for that.

Of course, these days, most people expect their antenna tuning to be automatic. With some Lego, though, you could refit your manual one, if you like.

13 thoughts on “Link Coupling Antenna Tuner Wordless Workshop

    1. I was thinking the same thing, but then I realized it just becomes part of the circuit. It’s only used for matching, so as long as it’s effect remains fixed, it shouldn’t matter. At worst it might waste a bit of power, but I don’t think it would effect operation at all.

  1. Nice project; I would have gone with a different enclosure; I have enough boat anchors……
    As far as link coupled tuners go….
    You will have to pry my Johnson KW Matchbox Out of My Cold, Dead, Lifeless Hands.

    I love the air gap between the Antenna and radio a link coupled tuner offers………

  2. Loved the CAD in the video, the best sort (even for me a child of the digital age) its so much more real and quicker to cardboard it up. The construction in general seems rather over the top, which I like up to the point it makes the floor collapse.

    I inherited a box of variable air gap capacitor thingies.. Being far to young to have ever used them I’m ashamed to say it took me some real thinking to figure out what they were.. Still got them all somewhere. Does seem like making your own might actually be more useful though as if you can’t get hold of a replacement for the one you somehow managed to trash trying to build a suitable match is trickier than building to your own specs again.

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