DXLook Blog

If you've ever activated a summit or chased SOTA activators, you know that mountain-top propagation has its own unique characteristics. Your antenna is elevated, you're often above local noise sources, and you might be running QRP power — but the question remains: where is your signal actually going?

DXLook's SOTA View is purpose-built to answer that question. It combines real-time activation data from the SOTA API with live propagation reports from WSPRnet, PSK Reporter, and RBN to show you exactly where summit activators are being heard around the world.

This post explains how the SOTA View works, what data it displays, and how to use it to improve your activations or maximize your chasing success.

What is SOTA?

Summits on the Air (SOTA) is an award program that encourages portable amateur radio operation from mountain summits. Each summit is assigned a reference code (e.g., W4C/WM-028), altitude, point value, and geographic coordinates.

Activators earn points by making contacts from qualifying summits, while chasers earn points by working activators on the air. The program combines hiking, radio, and propagation — making it a unique challenge in the amateur radio world.

For more information about SOTA itself, visit sota.org.uk.

How the SOTA View Works

The SOTA View on DXLook pulls together three critical data sources:

  1. Live SOTA Spots — Recent activation spots from the SOTA API (api-db2.sota.org.uk)
  2. Summit Reference Data — Complete summit information including name, altitude, points, region, and grid location
  3. Propagation Reports — Real-time reception reports from WSPRnet, PSK Reporter, and RBN

When you load the SOTA View, DXLook queries the SOTA API for recent activations within your selected time window, enriches that data with summit metadata, and then cross-references it with our propagation database to show you who heard the activator and where those signals went.

Filter Options: Callsign, Grid, Summit, or All

The SOTA View offers four filtering modes to help you zero in on the activations you care about:

1. Filter by Callsign

Enter an activator's callsign (e.g., KO4LIT) to see all summits they've activated recently, along with propagation paths showing where their signals were received.

Use case: You're chasing a specific activator and want to know what bands they're on and where they're being heard.

2. Filter by Grid

Enter a 4-character Maidenhead grid (e.g., FN31) to see all summit activations within or near that grid square.

Use case: You want to see what summits are active in your region or in a specific part of the world.

3. Filter by Summit

Enter a specific summit reference (e.g., W4C/WM-028) to see all recent activations of that summit, regardless of band or mode.

Use case: You're planning to activate a summit and want to see historical propagation patterns from that location — or you want to track a popular summit that's getting multiple activations.

💡 Pro tip: You can click any mountain icon (⛰️) on the map to automatically filter by that summit. This instantly reloads the view showing all recent activations from that peak.

4. No Filter (All Activations)

Select "No filter" to see a global view of all SOTA activations within the time window.

Use case: You want to explore current SOTA activity worldwide, spot band openings from summits, or just watch the action.

Time Window: From 15 Minutes to 24 Hours

The SOTA View includes a time filter that lets you control how far back to look for activations:

Why Time Windows Matter

SOTA activations are typically short-lived — an activator might only be on the air for 20-60 minutes before packing up and descending. A shorter time window (15-30 minutes) shows you what's happening right now, while longer windows (6-24 hours) give you a propagation retrospective showing where summits were heard throughout the day.

Caching optimization: Longer time windows are cached for 30 minutes, while shorter windows are cached for just 5 minutes to ensure you're seeing fresh data.

What the Map Shows: Summit Markers and Propagation Paths

When you load the SOTA View, here's what you'll see on the map:

⛰️ Mountain Icons (Summit Markers)

Each active summit is represented by a mountain emoji icon positioned at the summit's exact latitude and longitude. The icon size indicates activity level:

The icon is color-coded by band based on the most recent activation frequency:

Interactive Tooltips

Hover over any mountain icon to see:

Propagation Arcs and Receiver Boxes

If propagation data is available (meaning we found matching QSOs in our spots database within ±15 minutes of the activation), the map will draw:

  1. Great-circle arcs from the summit to each receiver location
  2. Grid boxes at the receiver's 6-character Maidenhead grid
  3. Callsign labels showing who heard the activator

Arc color matches the band color, and hovering over an arc shows:

This gives you a real-time propagation map showing exactly where the summit's signal went — perfect for understanding propagation patterns from elevated locations.

Band and Mode Filters

In addition to the SOTA-specific filters, you can also filter by band (160m through 2m) and mode (CW, SSB, Digital, or All).

Important Filter Behavior

When you filter by summit or select "All activations", the band and mode filters are ignored. Why? Because users typically want to see all activations of a specific summit regardless of what band or mode was used.

However, when you filter by callsign or grid, the band and mode filters are applied. This lets you focus on specific propagation conditions (e.g., "Show me all 20m FT8 activations in grid FN31").

Practical Use Cases for the SOTA View

1. Pre-Activation Planning

Before you hike up a summit, use the SOTA View to see:

Click the summit's mountain icon to filter by that specific peak and see historical patterns.

2. Real-Time Chasing

If you're chasing SOTA activations, set the time window to 15 or 30 minutes and watch for new spots. When you see a mountain icon appear:

3. Post-Activation Analysis

After an activation, set the time window to 6 or 12 hours and filter by your callsign. You'll see:

This is great for logging, reporting, and understanding what worked (and what didn't).

4. Summit Comparison

Want to know if a certain summit has better propagation than another? Filter by each summit's reference code and compare the propagation paths. Higher summits often show longer propagation paths due to better line-of-sight and reduced local noise.

5. Band Opening Detection

Set the filter to "All activations" and watch for clusters of mountain icons appearing on specific bands. If you see multiple summits on 10m or 6m suddenly getting long-distance reception reports, it's a sign of a band opening — and a good time to get on the air.

Technical Details: Data Flow and Caching

Here's what happens behind the scenes when you load the SOTA View:

Step 1: Fetch SOTA Spots

We query the SOTA API for recent activations based on your filters:

Step 2: Enrich with Summit Data

Each SOTA spot is enriched with data from the summitslist table:

Step 3: Cross-Reference Propagation Data

For each activation, we query our spots table for any QSOs involving the activator's callsign within ±15 minutes of the activation timestamp. We also filter by band to ensure we're only showing propagation on the same frequency as the SOTA spot.

This gives us the receiver locations (who heard the activator), which we then plot as arcs and grid boxes on the map.

Step 4: Group by Summit

Multiple activations of the same summit are grouped together and displayed under a single mountain icon. The tooltip shows all recent activations in reverse chronological order (most recent first).

Step 5: Cache and Serve

The final result is cached with a dynamic TTL:

This ensures fresh data without overloading the SOTA API or our database.

Frequencies and Modes: What to Expect

SOTA activators use a wide range of bands and modes. Here are the most common:

Band Frequencies Modes Notes
20m 14.060 MHz (CW), 14.285 MHz (SSB), 14.074 MHz (FT8) CW, SSB, FT8 Most popular SOTA band worldwide
40m 7.032 MHz (CW), 7.200 MHz (SSB), 7.074 MHz (FT8) CW, SSB, FT8 Great for NVIS and regional contacts
30m 10.130 MHz (CW), 10.136 MHz (FT8) CW, FT8 CW/digital only (no SSB)
17m 18.090 MHz (CW), 18.150 MHz (SSB) CW, SSB Less crowded, good for DX
15m 21.060 MHz (CW), 21.300 MHz (SSB) CW, SSB, FT8 Excellent for DX when open
10m 28.060 MHz (CW), 28.400 MHz (SSB) CW, SSB, FT8 Highly dependent on solar conditions
2m 144.174 MHz (FT8), 146.520 MHz (FM) FT8, FM, SSB VHF simplex and weak-signal modes

Many activators run QRP power (5-10 watts), so propagation paths are especially valuable for understanding how well low-power signals can travel from mountain summits.

Why Summit Propagation is Unique

Operating from a summit gives you several propagation advantages:

1. Elevation Gain

Your antenna is higher above average terrain, which improves line-of-sight paths and reduces ground losses. This is especially helpful on VHF/UHF.

2. Reduced Local Noise

Mountain summits are often far from power lines, industrial noise, and urban RFI. Your receive sensitivity is much better, allowing you to hear weaker signals.

3. Clear Horizons

With fewer obstructions (buildings, trees, hills), your takeoff angle is lower and clearer — great for DX on 20m, 17m, 15m, and 10m.

4. NVIS Propagation

On 40m and 80m, high-angle radiation (NVIS) from a summit can provide excellent regional coverage, filling in the "skip zone" that's often dead at ground level.

The SOTA View helps you visualize these effects by showing where your elevated signal actually went — often much farther than you'd expect from QRP power.

Tips for Using the SOTA View

⛰️ Click Mountain Icons

Don't just hover — click any mountain icon to instantly filter by that summit and see all its recent activations with full propagation data.

📡 Use Short Time Windows for Live Chasing

Set the time filter to 15 or 30 minutes when actively chasing SOTA spots. This keeps the map clean and shows only current activations.

🗺️ Use Long Time Windows for Analysis

Set the time filter to 6 hours when analyzing propagation patterns or reviewing your own activations after the fact.

🔍 Filter by Grid to Find Local Summits

Enter your home grid (or a grid near a hiking area) to see what summits are active nearby. Great for planning weekend activations.

📻 Check Propagation Before Switching Bands

If you're on a summit and considering a band change, use the SOTA View to see what band is currently showing the best propagation paths from your region.

🌐 Watch for Greyline Paths

SOTA activations during greyline hours (sunrise/sunset) often show enhanced propagation. Look for arcs crossing the day/night terminator on the map.

Data Sources

The SOTA View relies on these trusted sources:

All propagation data is cross-referenced by callsign, frequency, timestamp, and Maidenhead grid to ensure accuracy.

Final Thoughts

Whether you're an activator planning your next summit or a chaser tracking down activations, the SOTA View gives you a real-time propagation perspective that you can't get from spot lists alone.

You'll see:

SOTA is all about combining the outdoors with radio. Now you can combine it with real-time propagation visualization too.

See you on the summits!

73 de AK6FP Rodrigo https://dxlook.com