Spacecraft Re-Entry: High Freq Comm & Plasma Frequency

[Aniket1]

I recently read about the communication blackout during a spacecraft re-entry.. The reason given was the high density plasma formed whose plasma frequency is such that the communication waves do not penetrate it. Why don't we use a higher frequency for communication which is sufficient to pass through the plasma?

 

[AJ Bentley]

http://www.spaceacademy.net.au/spacelink/blackout.htm