Why do DX stations often transmit and receive on different frequencies?
Because the DX station may be transmitting on a frequency that is prohibited to some responding stations
To separate the calling stations from the DX station
To improve operating efficiency by reducing interference
All these choices are correct✓Bonne réponse
Explication
Working split moves the pileup off the DX station's transmit frequency so callers can hear it, it lets stations answer whose license class or national allocation does not permit transmitting where the DX station is transmitting, and the net effect is less mutual interference and a faster rate. All three statements describe the same practice.