Wireless Radio, 5G Etc..

Thread Starter

ben sorenson

Joined Feb 28, 2022
106
I know pretty much nothing about radio waves, etc etc just that a faster frequency equals to a shorter wavelength, however what I'm wondering what makes certain e.m waves more "valuable" to the companies that transmit them? Is it because it is at a higher frequency? Also, as far as "broadcasting" a signal and being able to receive it does it just all boil down to how "fast" a signal can be switched on/off then transmitted through a antenna that makes it all work?
 

Ya’akov

Joined Jan 27, 2019
6,856
Different bands have different propagation characteristics. Depending on the application a certain band might be more or less desirable for these characteristics. For example, relatively longer wavelengths like 700MHz and 900MHz are better at penetrating buildings making them useful for mobile phone service.

Shorter wavelengths allow for more granularity in coverage since they become more and more dependent on line of sight. This means that if you want to have many small transceivers, like in the 5G system, you can put more in the same area without interfering to increase coverage and bandwidth.

Higher frequencies can also have higher bandwidth. Since the alternation of the signal is needed to send symbols, the faster the signal can change the more information per unit time you can handle.

For consumer products there is also the consideration of an effective antenna. The shorter the wavelength the shorter a good antenna has to be. Higher frequencies make decent antennas in watches and compact phones possible.
 

MrChips

Joined Oct 2, 2009
27,695
I know pretty much nothing about radio waves, etc etc just that a faster frequency equals to a shorter wavelength, however what I'm wondering what makes certain e.m waves more "valuable" to the companies that transmit them? Is it because it is at a higher frequency? Also, as far as "broadcasting" a signal and being able to receive it does it just all boil down to how "fast" a signal can be switched on/off then transmitted through a antenna that makes it all work?
Here are some considerations that determine the effectiveness of EM waves at different frequencies.

Longer wavelengths can bend around corners. Shorter wavelengths are limited to line-of-sight, don't get around barriers very well, and gets reflected causing interference.

The Earth's ionosphere cause EM waves to refract around the curvature of the Earth, especially at longer wavelengths. The phenomenon of "skip" is well known among CBers and HAM operators where you can receive a signal from a transmitter thousands of miles away. Multiple skip from the same transmission is also well known.

When the RF carrier is modulated the transmitted signal occupies a wider bandwidth. Thus the ratio between bandwidth and carrier frequency diminishes as the frequency increases.
 
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