I’ve seen radio waved depicted in two different ways that seem at odds with one another. the first is something like [this](https://upload.wikimedia.org/wikipedia/commons/thumb/3/3d/Wireless_tower.svg/75px-Wireless_tower.svg.png), with the waves spreading out from a point source in all directions. the second is like [this](https://upload.wikimedia.org/wikipedia/commons/thumb/d/d1/Cross_linear_polarization.gif/330px-Cross_linear_polarization.gif) with the radio wave moving in a “tube” constrained by its own parameters.
since we can’t see them, radio waves remain a bit abstract, but both of these visualizations can’t be correct at the same time… or can they? can someone as to what the real picture would “look” like?
many thanks!
In: 3
Any depiction that shows a squiggly line is abstract – the wave follows a straight path.
The line represents the strength of local fields, and is no representation of the actual movement or physical shape of the radio wave.
A wave cannot be perfectly constrained to a beam, but with shorter waves and wider beams, you can get pretty close. Radio waves really don’t form good beams, because the waves are so long, but you can point them roughly in one direction. That’s what big satellite dishes do.
Regular antennas actually also limit the direction – the antenna does not transmit in the direction it’s pointed. It *only* transmits sideways.
Latest Answers