I am attempting to design an antenna similar to a TTFD, double zepp or array of end fed wires, with a sinusoidal, with the period of the wavelength, spacing that causes additive waves on the target frequency(assume proper phase alignment,180 degrees, and a constant velocity factor for this question).

drawing of 2 vertical sine waves one of them is phase shifted 180 degrees

Assume the image is a top down view of the wires forming perfect sine waves :)

The feed point locations should be at +90 and -90 degrees offset.

I barking up the wrong tree?

The thought process behind this: Invert the phase of half of the signal to null the desired frequency, and correct the phase disparity through the physical spacing of the wires.

This design would probably be very low bandwidth and thus impractical for most uses, but would it work at all? And what about noise reduction?

  • 2
    $\begingroup$ Could you clarify your question by editing it to include a diagram of what your planned antenna design is, and which part has the ‘sinusoidal spacing’? $\endgroup$
    – Kevin Reid AG6YO
    Apr 20, 2020 at 0:06
  • $\begingroup$ Welcome to ham.stackexchange.com! $\endgroup$
    – rclocher3
    Apr 20, 2020 at 2:47
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    $\begingroup$ Do you meant that, rather than being linear in three-dimensional space, the plane containing the parallel wires of the folded dipole follows a sinuous path described by a sinusoid? An antenna fitting this description was popular for FM broadcast reception a few decades ago. $\endgroup$
    – Brian K1LI
    Apr 20, 2020 at 8:29
  • $\begingroup$ Hello and welcome. Can you explain in more detail what you're trying to achieve in the first place? The description doesn't sound like a folded dipole - "sinusoidal spacing" doesn't ring a bell (or appear on google). Nothing wrong with trying to make the antenna better reject unwanted frequencies if that's your goal, but a folded dipole is the not very good for that, being so wide band and well matched. $\endgroup$
    – tomnexus
    Apr 20, 2020 at 14:57
  • $\begingroup$ @tomnexus, Thank you and every one for the welcome. I think this may end up in the crazy design pile, but I thought I would try to ask first. $\endgroup$
    – KX4UQ
    Apr 21, 2020 at 23:13


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