Schumann App Charts: Find the Station Behind Your Reading

Look for the observatory name beside the chart you’re reading. Nagycenk in Hungary can supply the number while Etna in Sicily supplies a picture. And if the number is an app’s own score, several sources may have gone into it.

Key takeaways

• Open the source details for the individual panel. A single screen can put a Hungarian reading beside an image from Sicily.
• Read the time of the last observation. Your phone can retrieve an old measurement just as quickly as a new one.
• Keep the unit attached to the number. Hertz tells you where a peak sits in frequency. An amplitude tells you how strong a signal looks on the stated scale.
• Check what happens during a gap. Some services name a substitute station. Others pause a score until they have usable input again.
• Save the original link with your note. Anyone you share it with can then check the station, the time and the full legend.

1. The question at home

A friend sends a picture of a Schumann chart with a bright stripe across it. You open your own app and find a quiet-looking line. One of the kids asks the obvious question. “Which one shows what’s happening here?” Before you try to explain the stripe, tap the little source link. If it takes you to an observatory in Hungary, you already have part of the answer. Someone made a measurement in Hungary. There’s no instrument in that chain taking a reading in your kitchen.

Start with the panel that caught your eye. On the public Schumann Pulse station display, the station selector offers a Siberian source, Nagycenk in Hungary and Etna in Sicily. The number at the top and the spectrogram you can open further down may come from different places. A spectrogram is a picture of how the signal at different frequencies changes over time. When somebody crops it for a message, the part that identifies its origin is easy to lose.

There’s another possibility. If you’re looking at ResonanceOne’s Activity Index, several inputs contribute to the answer. The provider gives its Schumann input a 70% weighting, geomagnetic activity 25% and solar flare activity 5% (ResonanceOne’s index definition). Asking “Which station supplied the Schumann part?” makes sense. Asking for the station that recorded the whole score leads nowhere, because the app calculates it. The SolarHealth dashboard guide explains the different readings you may find together on a screen.

2. What physics allows

Lightning gives rise to electrical and magnetic disturbances. Some of that energy travels around the world in the space between the ground and the lower ionosphere, an electrically conducting region high in the atmosphere. This space favours certain frequencies. The lowest broad peak usually sits near eight cycles per second, or eight hertz. That’s the origin of the familiar 7.83 Hz label. An app can print that reference value every day without measuring the peak afresh. ResonanceOne explicitly identifies its frequency field as just such a reference (provider’s frequency definition; research on the Earth–ionosphere cavity).

What reaches an instrument depends partly on where the lightning is relative to it. The instrument matters too. Near Nagycenk, the observatory plots two horizontal components of the magnetic field and one vertical component of the electric field. To estimate the frequencies and amplitudes of its first three resonance bands, it uses that vertical electric recording (Nagycenk instrument report). At Nicolosi, on the slopes of Etna, the observatory describes a coil that picks up changes in the magnetic field (Etna receiver and displays). Both instruments listen to natural electromagnetic activity. They give you different quantities to put on a graph.

You can see the distinction without doing the maths. On a spectrogram with time running across and frequency up the side, follow one band from left to right. Where the instrument has valid data, a change in colour at the same height shows a change in displayed strength at that frequency, provided the scale stayed fixed. If the centre of the band moves up the frequency axis, that’s a different observation. Etna even displays the output of one coil over different time windows. Two pictures can look quite different before a second station enters the story.

3. What tests show

A saved reading lets you check what the labels actually mean. On 8 November 2026, Schumann Pulse preserved a card identifying Nagycenk as the substitute for its Siberian source. The card gives both an observation time and a capture time. You can still inspect the values that went with those times after the live page has moved on (open the dated card).

On the saved card	What you can tell from it
Source: Nagycenk, Hungary	The app used the Hungarian source for this reading. Etna had a separate spectrogram.
Measured 15:40 UTC · captured 16:11 UTC	The latest observation shown was already 31 minutes old when the card was saved.
First-mode amplitude: 3.7	This was the app’s 30-minute level, in relative source units.
First-mode frequency: 8.0 Hz	This was the estimated position of the first peak at the stated observation time.

Now look at the same date from another service. ResonanceOne’s status page reported that it lacked usable Schumann input from both its usual Tomsk source and its Etna backup. It put its last usable reading at 19:00 UTC the previous day. Its solar and geomagnetic inputs were still available. So one service could show a Hungarian observation while another had paused its index. The notice describes what reached the service. It doesn’t tell us which piece of equipment, if any, failed at an observatory (ResonanceOne’s dated service record).

There’s also a physical reason to care about the station even when all the feeds are working. On 15 February 2023, a satellite tracked a line of thunderstorms moving across South America. Researchers compared its path with the Hungarian electric-field recording. The third resonance peak there varied by about 0.4 Hz over the hours they examined. The first peak showed no comparable excursion during the highlighted interval. Their model reproduced part of the third peak’s movement and underestimated its size. If all you’d received was the message “Earth’s frequency changed”, you’d have lost both the identity of the peak and the place where it was observed (Sátori and colleagues, 2024, section 7).

Where each claim stands.

• Nagycenk estimates its first three resonance peaks from the vertical electric-field recording: supported by the observatory report.
• On the saved November card, 3.7 and 8.0 can both describe the same band, because the labels assign them to different properties: supported by the saved card.
• The 15 February 2023 third-peak excursion followed South American storms: supported as a single case study, with the model reproducing only part of the size.
• A difference between two screens just after a gap comes from a station switch: untested; check the source change at that time first (provider’s fallback method).
• A distant station reading lines up with a restless night: untested.

4. What you can do anyway

Next time a chart catches your attention, leave it open and follow the reading back to its source. This works with a phone and a scrap of paper. The useful result is a short note you could hand to someone else and have them find the same observation.

1. Name the panel and the place. Write down the app, the panel title and the named observatory. If the credit only says “live data”, open the information icon or source page. If the trail ends there, write “station unspecified”.
2. Copy the observation date, time and time zone. Look at the last plotted sample or the time printed on the original chart. Keep the time you opened the app in a separate field. UTC gives you a shared clock when comparing countries, especially around midnight.
3. Copy the quantity exactly as labelled. “First peak, Hz”, “first-mode amplitude, relative units” and “activity index, 0–100” belong on different lines. If the legend gives no unit, leave the unit open. A colour alone won’t supply it.
4. Test one comparison. Open the credited observatory or a second viewer. Match the station, field component and time window. Check whether both displays show individual samples or averages. If both reuse the same station chart, you’ve traced its origin. An independent observation would require a separate instrument.
5. Keep the detail you set out to explore. If you opened the app because you had a restless night, write down what you noticed before looking through the charts. “I was awake before dawn” is a perfectly good observation in its own right. Put your local time beside it, then add the distant station reading in a separate column. A single overlap can give you a question to come back to on ordinary nights, too.

The next time that friend sends a bright stripe, you’ll have a better question than “How high did it go?” Try “Can you send the original link with the station name still showing?” It takes a moment, and you might discover you’ve both been looking at the very same instrument all along.

Related on SolarHealth

• Six solar and geophysical measurements and what they track
• Space weather dashboard basics
• Follow the SolarHealth app project

Sources

1. Schumann Pulse. Station selector, source notes and fallback policy and saved Nagycenk reading from 8 November 2026.
2. ResonanceOne. Activity Index inputs and nominal frequency field and Schumann feed availability and backup procedure.
3. Szabóné André K. and colleagues (2021). Automatic display of ELF measurements recorded in the Széchenyi István Geophysical Observatory. Geophysical Observatory Reports, 35–40.
4. Etna Radio Observatory. ERO–Etna Park receiver specifications and time-window settings.
5. Sátori G. and colleagues (2024). How do Schumann resonance frequency changes in the vertical electric field component reflect global lightning dynamics at different time scales? Journal of Geophysical Research: Atmospheres, 129, e2024JD041455. University repository copy.