Who Has Not Heard LDEs?

• A year-long test conducted at Cambridge University in 1948 to find LDEs transmitted and recorded 27,000 test signals at 13.4 and 20.6 MHz, without finding a single LDE. Their antennas were directive upward, as their hypothesis was that LDEs were caused by electron clouds in space.

• A 1960's survey of ship-to-shore radio-telegraph operators at Half Moon Bay, California revealed that none had ever heard an LDE, despite communicating at various distances on various bands around the clock for years.