When you first open DXLook, one of the main visualization modes you'll see is the Cluster View. It might look like a cloud of dots — some in dense patches, others more isolated — but behind those points lies a live, detailed map of global HF activity.
This post explains how we calculate the Cluster View, what it’s showing, and why it’s such a powerful tool for operators looking to understand real-time propagation.
What the Cluster View Actually Shows
At its core, the Cluster View shows real reception reports. These are not predictions, summaries, or models — they are direct, timestamped events where Station A heard Station B on Frequency X using Mode Y with SNR Z.
Each point (or "spot") represents a confirmed exchange of RF information. These reports are sourced live from multiple networks:
- PSK Reporter
- WSPRnet
- Reverse Beacon Network (RBN)
- DX Clusters
If you’re seeing activity on the Cluster View, you can trust that real radios are making those contacts or hearing those signals right now.
How We Process the Data
Even though the data sources vary, the processing logic is unified:
1. Time Filtering
We only display spots from the last 5 minutes. This gives a real-time view that’s constantly evolving and never stale. It also prevents older activity from cluttering the picture and misleading the user.
2. Grid Perspective Filtering
To keep the view relevant to your region of interest, we filter based on the selected 4-character Maidenhead grid (e.g., CM87).
Instead of just showing spots within that grid, we include all spots where either the sender or the receiver is located in that grid or any of its 8 immediate neighbors. This ensures that:
- You don’t miss paths crossing near your QTH
- You still capture activity just outside your exact grid square
This approach keeps the view local enough to be relevant, but wide enough to be informative.
3. Band and Mode Filtering
You can filter the data further by selecting a specific band (like 20m or 10m) and a specific mode (FT8, CW, SSB, etc.). This lets you focus on the slice of activity you care about most, especially when looking for DX openings or testing antennas.
4. Positioning
Each spot is represented by the midpoint between sender and receiver. Why? Because it gives a realistic sense of where the signal actually traveled over the globe — a more meaningful placement than just plotting the transmitter or receiver alone.
Why the Cluster View Matters
The Cluster View isn’t about statistics — it’s about real-time awareness. Here’s what makes it valuable:
🔭 Spot Early Band Openings
Sometimes you'll see scattered points start to light up over a path — say between the U.S. West Coast and Japan on 17m. That's often the first sign that a band is beginning to open, long before summary views or MUF overlays catch up.
🔍 Investigate Individual Propagation Paths
Because each spot is raw and uncompressed, you can zoom in to see:
- The exact callsigns involved
- Signal strength (SNR)
- Distance in kilometers
- Mode used (FT8, CW, etc.)
This is especially helpful when comparing how well different stations are being heard — or how well you’re getting out.
🛰️ Validate Your Station’s Performance
If you’re running an experiment — changing antennas, adjusting power, or testing a new location — the Cluster View shows how your station is actually being received across the world in near real-time. It’s a propagation lab you can watch live.
🌐 Explore Global Activity Patterns
You can zoom out and look at propagation patterns continent-to-continent, spot trans-equatorial paths, greyline activity, or even strange anomalies like long-path echoes.
🛠️ Great for Debugging
If someone says “10m is dead,” but you see spots lighting up across 10m in the Cluster View — you have the data to say otherwise. It's also good for verifying if your local station is getting out during contests or events.
How It’s Different From Other Views
Compared to the Summary View (which aggregates activity into grid-based averages) or the MUF View (which models Maximum Usable Frequency based on path SNR), the Cluster View is:
- Raw
- Direct
- Instantaneous
It doesn’t smooth out noise or try to infer regional trends. It simply answers: Who is hearing whom, right now, on this band, near this grid?
Final Thoughts
Propagation is always in motion. Solar activity, greyline movement, geomagnetic storms — they all shift the boundaries of what’s possible on the HF bands.
The Cluster View gives you a direct line of sight into this shifting landscape. It’s not trying to predict anything. It’s just showing you the truth: a live, breathing record of global RF activity.
Whether you're a DX chaser, a technician experimenting with antennas, or a new ham trying to understand why some days work better than others — this view helps you learn by seeing the invisible.
73 de AK6FP
Rodrigo
https://dxlook.com