Radio waves can travel through concrete walls to some extent, but their ability to penetrate depends on various factors, including the thickness and composition of the wall, the frequency of the radio waves, and the power of the radio signal. Generally, lower frequency radio waves (e.g., AM radio) have better penetration capabilities compared to higher frequency waves (e.g., Wi-Fi or Bluetooth).
Concrete walls can attenuate or weaken radio waves as they pass through due to the absorption and scattering caused by the building materials. This means that the signal strength on the other side of the wall may be reduced compared to the signal strength in an open space.
On the other hand, metal fences and walls made of conductive materials, such as steel or aluminum, can block or significantly attenuate radio waves. Metal objects can reflect or absorb radio waves, preventing them from passing through. This effect is particularly noticeable for higher frequency waves like those used for Wi-Fi or cellular signals. Metal surfaces act as barriers to these waves, effectively blocking their transmission.
It's worth noting that radio waves can exhibit diffraction and reflection phenomena, which means that under certain circumstances, they can bend around obstacles or reflect off surfaces to reach the other side. However, the effectiveness of these effects depends on the specific conditions and characteristics of the waves and obstacles involved.
In summary, radio waves can partially penetrate concrete walls, but their strength may be weakened in the process. Metal fences and walls, however, can block or significantly attenuate radio waves, particularly at higher frequencies.