DX is amateur shorthand for distant. There is no specific distance defined as being regarded as DX. It is entirely up to the amateur to use his/her judgement as to what they consider as DX.
The DX Cluster is a world wide network of connected computers where radio amateurs and SWL’s (Short Wave Listener) send “DX spots” by uploading relevant information. This short piece of information containing details of DX stations they have heard or made contact with is called a “Spot”. As a result these spots give other stations that are receiving the spots some idea of who can be heard and where in real time.
A typical spot will include the time the spot is originally sent, the callsign of the station being “spotted”, the frequency the spotted station is using and his country. A few other pieces of information may be added such as a comment from the sender.
Live DX Cluster
A live feed is shown below. “de” is the sender the spot. “dx” is the station heard, “freq” is the frequency in MHz. “time” is very obviously, the time in UTC and date the spot was sent.
The table will update automatically as spots are sent.