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Radio waves are waves, which have many similarities to other waves, which allows us to consider analogies. Here's one: if you put your ear firmly to the end of a long tube, the sound will be different than if you weren't listening through the tube. Instead of hearing the usual mix of high-pitched sounds, low-pitched sounds, and mid-range-pitch sounds, you ...


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Consider a swing, like the kind found at a playground. If you sit on it and shift your weight forward and backward at just the right rhythm, you can get the swing to go very high. It goes high because the combination of the swing and the mass of your body is resonant at a particular frequency. When you shift your weight to "pump" the swing, you add ...


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Propagation of waves in free space is both electronic and magnetic in nature. Both field components combine to induce the movement of electrons in an antenna. All frequencies are added together to make up the radio spectrum (a single entity per polarization, Horizontal and Vertical). The entire thing is combined into a grand complex wave. For completeness, ...


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It's not like mixing paint. That's because it's a just a simple sum or linear mix, rather than a chaotic or non-linear mix with intermodulation products. It's like a duet with a soprano and a bass singer. You can easily transcribe the low frequency bass voice and semi-ignore the soprano, or vice versa, because the frequency ranges are so different, and ...


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There's something called the "principle of superposition" — in a linear system (which we can consider an antenna and the "front end" of a receiver to be), if the current resulting from signal A is $C_A$, and the current resulting from signal B is $C_B$, then the current resulting from both signals at once is simply $C_{A}+C_{B}$. Even if ...


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