What is a DX cluster?

A DX cluster is a network of linked servers on which amateur radio operators post the callsign, frequency and time of interesting stations they hear. A single post is called a spot. Because thousands of operators worldwide feed the same network, the cluster works as a live map of which bands are open and where the rare stations are, minutes before that information would reach you by tuning across the band yourself.

How to read a DX spot

Every spot carries four pieces of information: the callsign of the station being reported, the frequency in kilohertz, the callsign of the operator who posted it, and the time in UTC. A spot on 14025 kHz tells you the station is near the bottom of the 20 metre band, which by convention is CW. Spots above roughly 14150 kHz on the same band will be SSB. The spotter callsign matters because a station reported by a European operator is not necessarily audible in North America.

Using the cluster to judge band conditions

The volume of spots on a band is a fast proxy for whether that band is open. A 10 metre band producing hundreds of spots an hour is alive, while the same band with a handful of spots is closed for most paths. Comparing SSB, CW and FT8 activity on a band also tells you which mode is getting through, since weak signal digital modes keep working long after voice contacts have become impossible.

Frequently asked questions

What does DX mean in amateur radio?

DX means distance, and refers to a station that is far away or hard to reach. On HF it usually means another continent or a rare country, while on VHF a contact of a few hundred kilometres can already count as DX.

Is a DX cluster free to use?

Yes. The DX cluster network is run by volunteers in the amateur radio community and is free to read. The live feed on this page requires no login and no software.

Why can I not hear a station that has been spotted?

A spot only proves that the operator who posted it could hear the station. Propagation is path dependent, so a station easily worked from Spain may be inaudible from Scotland at the same moment. Check the spotter location and look for spots posted by stations near you.

What is the difference between a DX cluster and the Reverse Beacon Network?

A DX cluster is fed by human operators posting spots by hand. The Reverse Beacon Network is fed by automated receivers that continuously decode CW and digital signals and report everything they hear, so it gives wider and more objective coverage of who is transmitting.

What the cluster usually looks like

The feed above changes minute by minute, so here is the part that does not: the shape of a normal day on the cluster. Twenty metres carries the largest share of spots across the whole 24 hours and is the band most likely to be open somewhere at any moment. Forty metres builds through the late afternoon and stays useful all night. Fifteen and ten metres are daytime bands that depend heavily on solar flux, and in a quiet part of the cycle ten metres can produce almost nothing for weeks and then open dramatically for an afternoon.

Mode distribution is just as consistent. FT8 produces far more spots than every other mode combined, because it is machine generated and reported automatically. CW and SSB spots are posted by human operators, so their volume tracks when people are actually at the radio: evenings on weekdays, and a very large spike across a contest weekend. If you see the cluster suddenly carrying several times its usual volume, check the contest calendar before assuming the bands have opened.

Geography follows the same rules as propagation. European and North American spots dominate simply because that is where most of the operators are, so a quiet continent on the list often means quiet operators rather than a closed band. To judge whether a path is genuinely open rather than merely unpopular, compare the cluster with the current propagation score, or listen for a specific beacon on the NCDXF beacon monitor, which transmits on a fixed schedule whether anyone is listening or not.

How do I connect to a DX cluster with telnet?

Most logging programs have a cluster client built in: you give it a node address and port, usually 7300 or 8000, and your callsign as the login. You can also connect with a plain telnet client. The page above needs none of that, because it reads the same network and renders it in your browser with no login.

Do I need special software to use a DX cluster?

No. Software helps if you want spots pushed straight into your logging program or onto a bandmap, but the information itself is public and readable in a browser. Start by watching, and add software when you find yourself wanting the spots to do something automatically.

What do the numbers in a DX spot mean?

The frequency is in kilohertz and tells you where to tune, and the time is in UTC. The frequency also implies the mode by convention: near the bottom of a band you are almost certainly looking at CW, the middle carries the digital segments, and the upper part is SSB. A spot on 14025 is CW; one on 14250 is voice.

What does the spotter callsign tell me?

It tells you where the report came from, which is the single most useful thing on the line after the frequency. Propagation is path dependent, so a station spotted by an operator near you is far more likely to be workable than the same station spotted from another continent. When you cannot hear something that has been spotted, look at who spotted it before concluding your station is at fault.

What is a busted spot?

A busted spot is one with the callsign copied wrongly, usually because the spotter was working a weak signal. They propagate quickly because other operators re-spot what they see rather than what they hear. If a callsign does not resolve to anything sensible, or the same station appears with two slightly different callsigns, treat both with suspicion and confirm by listening.

How do I get spotted myself?

By being worth spotting: call CQ on a clear frequency and be findable. Someone who works you may post you. You should not spot yourself on most networks, since self spotting is discouraged outside specific activity programmes such as POTA and SOTA where it is expected. If you call CW, the Reverse Beacon Network will report you automatically whether anyone works you or not.

Why are there so many FT8 spots?

Because FT8 reporting is automatic. Stations running WSJT-X upload what they decode to reporting networks continuously, so the volume reflects how many receivers are switched on rather than how interesting the activity is. Human posted CW and SSB spots are far rarer and, for that reason, usually more meaningful.

What is PSK Reporter and how does it differ from a cluster?

PSK Reporter collects automatic reception reports from digital mode software: it tells you who was heard where, by machines. A DX cluster carries spots posted by people about stations they think are worth working. The first is a broad and objective picture of propagation; the second is a filtered, human view of what is interesting. This page merges both.

What is a DXCC entity?

A DXCC entity is a place that counts as separate for the DX Century Club award. The list is maintained by the ARRL and does not map onto countries: some countries contain several entities, and remote islands often count as entities of their own. Chasing entities rather than countries is what most of the DX activity on the cluster is ultimately about.

What time are cluster spots shown in?

UTC, like everything else in amateur radio. Using one clock worldwide removes any ambiguity about when a spot was posted, which matters when a spot only stays useful for a few minutes.

Can I trust a spot for a station I cannot hear at all?

A spot proves only that one operator heard that station at that moment. It is evidence about a path, not about yours. Check the spotter’s location, look for other spots of the same station from stations nearer you, and compare against current conditions before deciding whether the band is closed or the station has simply moved on.

More tools on this site

The cluster tells you what people are hearing. To work out whether a band should be open at all, use the HF propagation score. To test a specific path on a fixed schedule, use the NCDXF beacon monitor. To find out why the bands suddenly got busy, check the contest calendar. And for passes of the amateur satellites over your own station, see the satellite tracker.