Radio signal propagation refers to the way in which radio signals travel through the environment. There are several factors that affect radio signal propagation, including:
Frequency: Different frequencies have different characteristics when it comes to signal propagation. For example, higher frequency signals (such as those in the microwave range) are more easily absorbed by buildings and trees, while lower frequency signals (such as those in the VHF and UHF range) can travel further and more easily pass through obstacles.
Power: The strength of a radio signal can also affect how well it propagates. Generally, a stronger signal will be able to travel further than a weaker one.
Antenna type: Different types of antennas are more or less efficient at transmitting or receiving a signal depending on the frequency, waveform and other factors.
Obstacles: Various types of obstacles, such as buildings, trees, and hills, can block or reflect radio signals. This can lead to signal shadowing, multipath or diffraction.
Weather conditions: The weather can have a significant effect on radio signal propagation. For example, ionized or charged particles in the atmosphere can reflect signals, allowing them to travel further. On the other hand, humidity and atmospheric gases can absorb signals.
Some common propagation methods are:
Ground wave propagation: the wave travels along the surface of the Earth, and it is mostly used by low frequencies.
Line of sight propagation: This type of propagation is generally limited to the horizon, and it requires a clear view between the transmitter and receiver.
Sky wave propagation: Signals are reflected by the ionosphere to travel over long distances. This method is used by medium and high frequencies.
Tropospheric propagation: Signals that travel through the lower levels of the atmosphere, it can be affected by temperature inversions and atmospheric pressure.
It is important to keep in mind that signal propagation can vary greatly depending on the specific environment, and it can be affected by many other factors. There are many tools and models available to help predict and understand signal propagation for a given scenario, such as ITU-R P.526 or Okumura-Hata.