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## Main Question or Discussion Point

if you fed a rectangular waves to a radio antenna, would it still produce radio waves? does it have to be a sine wave?

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if you fed a rectangular waves to a radio antenna, would it still produce radio waves? does it have to be a sine wave?

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FactChecker

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No, it does not have to be a sine wave. In fact, a rectangular wave can be thought of as a specific sum of sine (and cosine) waves of various frequencies. That is the basis of the Fourier series. The antenna will respond to each sine wave as though it was not part of a rectangular wave, then all the responses to the sine waves can be summed to get the total antenna response to the rectangular wave.

Shown below is a sequence of better approximations of a square wave using more terms in the Fourier series. Each line is plotted a little higher so that you can see them separately. Clearly, the more terms there are, the closer it gets to a square wave. An antenna will respond to each sine wave as though it is alone. Then the individual responses can be summed to get the total response.

Shown below is a sequence of better approximations of a square wave using more terms in the Fourier series. Each line is plotted a little higher so that you can see them separately. Clearly, the more terms there are, the closer it gets to a square wave. An antenna will respond to each sine wave as though it is alone. Then the individual responses can be summed to get the total response.

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Of course, it would produce radio waves but true broad-spectrum mess. Square wave can be simply turned into decent sine wave by inserting a loading coil between output of generator and an antenna.if you fed a rectangular waves to a radio antenna, would it still produce radio waves? does it have to be a sine wave?

The principle is same as in this video. This would make antenna more or less electrically short though.

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FactChecker

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A single square wave contains several sine waves of different frequencies and amplitudes. It would be possible to tune to any one of those and tune out the others (although not completely). The amount of power lost by tuning out the other frequencies depends on the response of the filter to the other frequencies.Of course, it would produce radio waves but true broad-spectrum mess. Square wave can be simply turned into decent sine wave by inserting a loading coil between output of generator and an antenna.

The principle is same as in this video. This would make antenna more or less electrically short though.

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It also depends on the frequency of square wave. For example if that frequncy is 3x higher than quarter wave resonant frequency system with loading coil, than the response of the system to the 3A single square wave contains several sine waves of different frequencies and amplitudes. It would be possible to tune to any one of those and tune out the others (although not completely). The amount of power lost by tuning out the other frequencies depends on the response of the filter to the other frequencies.

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sophiecentaur

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So the question in the OP doesn't make a lot of sense in the practical world. However, RF antennae are usually capable of handling a

Perhaps that was what the OP really meant.

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