How to harness the unused radiowaves coming from cell sites?
3 Discussions
This could actually be a great though experiment questions.

Tesla would disagree with everyone's answers and find a great way to change the way we design antenna towers and totally redesign our form of long distant communication to be more energy efficient and less EM pollutant

The truth is the tower expands a good deal of energy, but it's radiated out in the shape of a bloom, like giant flower petals. The dispersion of this energy is what makes it difficult to concentrate and re-collect. In fact the amount of energy that is used by detection is small, meaning that most of the energy dispersed in actually lost or conducted else where probably >80-95% totally lost to achiever average coverage

Now imagine if we have some sort of EM net that, some macro resonant Faraday cage that has the ability to harness back even 80% of all the power admitted out from all EM radiation, this would not only recycle back energy, it could be used to protect against EM pulses, and other form of EM harvesting as our Ozone continues to deplete and other form of solar EM radiation that's not within the infrared to ultraviolet get penetrated onto the earth's surface, or some perhaps even that who escape our earth natural protective magnetic field, the application would be a theoretical break through.....or even better we create more resonance devices so that only what's needed is used, like I say the thought experiment of how we can recycle EM energy is something that few have explored enough till we have found radical natural solutions ......like good old Nikola Tesla
There is really not much energy to be harvested..

Radiowaves coming from cell towers have been purposefully designed and engineered to emit as little energy as possible while still making information transfer possible. The antennas on your radios and phones are extremely sensitive to these signals but they need an amplifier to convert those signals into electrical pulses to power your speaker.

It's a nice side project to teach your kids about energy carrying waves but i wont put my money on powering a lightbulb from radiowaves anytime soon.
By "harnessing unused radio waves" and the question being categorized in "energy" I guess you are referring to harnessing the effective radiated power from cell site antennas. The power from a cell site isn't really worth trying to harness to do anything other than communication. It's not like listening to an AM station on a crystal radio. Cell sites actually tend to use the least amount of power necessary for the network to work. That is one of the reasons cell sites tend to be clustered in more populated areas and the cell sites are close enough to overlap in range so that a cellphone can switch from using one tower to another seamlessly.