7A1 Understand the reasons why some stations may use split Tx and Rx frequencies within a frequency band.
Sometimes, and especially with DX stations who may call CQ and end with "CQ up 5" at the end of the initial over, indicating that they are listening on a different frequency than they are transmitting on, often used for possible pileups where several stations will be trying to contact a single special or rare station.
Such practice is called operating "split operating" and it takes a certain amount of skill to work a DX operator working split mode and even more if you decide to split frequencies.
Operating split frequencies helps to manage a pileup of station who are calling to reply to the CQ call. By using a split frequency the DX operator keeps his transmit frequency clear so that the callers will hear him well making the exchange go more smoothly. He also has the opportunity to spread out the calling stations on several frequencies near his transmit frequency.
Additionally when working via a repeater on the mainly the VHF/UHF bands you are using a split frequency for transmit and receive ! That is why you have offset settings to program into your radio.
Please also remember that in the Intermediate section you learned about RIT and XIT functions on some radios, these 2 functions can help with running the split set up for DX communication to avoid a pile up.
The origin of some of the text on this page is from the RSGB with additions by the web master