C-band is known for being less susceptible to rain fade compared to other satellite frequency bands such as S-band, L-band, and Ku-band. Rain fade refers to the attenuation or loss of signal strength that occurs when rain or other atmospheric conditions interfere with the transmission of electromagnetic waves between the satellite and the ground station.

The reasons why C-band is less susceptible to rain fade are as follows:

1. Lower Frequency:
- C-band operates at a lower frequency range of around 4 to 8 GHz.
- Lower frequencies have longer wavelengths, which allows them to penetrate raindrops more effectively.
- Raindrops have a smaller impact on the signal at lower frequencies, resulting in less attenuation.

2. Absorption by Oxygen:
- C-band experiences less absorption by atmospheric gases, particularly oxygen.
- Oxygen molecules in the atmosphere absorb electromagnetic waves at higher frequencies, such as Ku-band and Ka-band.
- This absorption leads to a higher level of attenuation, especially during heavy rainfall.

3. Scattering Effects:
- C-band experiences less scattering of the transmitted signal due to raindrops.
- Scattering occurs when the electromagnetic waves interact with the raindrops and deviate from their original path.
- At higher frequencies, such as Ku-band, scattering is more significant, leading to increased signal loss.

4. Availability of Backup Frequencies:
- In addition to the above factors, C-band is also advantageous as it has a larger bandwidth allocation.
- This allows for the provision of backup frequencies within the C-band spectrum.
- If rain fade occurs on a particular frequency, the satellite operator can switch to a different frequency within the C-band to maintain signal continuity.

Overall, the combination of lower frequency, reduced absorption by atmospheric gases, minimal scattering effects, and availability of backup frequencies make C-band less susceptible to rain fade compared to other frequency bands commonly used for satellite communications.