How Dare You Transmit at 1.4 GHz!

It was launched to measure moisture, but NASA's SMAP satellite has become an unlikely player in the world of electronic warfare. I stumbled upon this fascinating story while analyzing public data from the satellite, and what I found is both astonishing and unsettling.

In January 2025, I started pulling data from the SMAP satellite's L1B brightness temperature files. At first, I was intrigued by the usual readings – soil moisture and ocean salinity. But then I noticed something peculiar. Certain areas in the 1.4 GHz band were emitting extremely high temperatures, well beyond what could be natural.

This frequency is supposed to be quiet, with strict regulations on transmission to prevent interference with other signals. The L-band, where SMAP operates, is a protected slice of the spectrum that's reserved for peaceful Earth observation. But when you inject hundreds of watts of RF into this band, SMAP can't ignore it. The brightness temperature spikes past 360K, indicating some sort of high-power jamming or spoofing emission.

What caught my attention was that these anomalies didn't occur randomly. They seemed to follow a pattern, often aligning with military signals and interests. Ukraine, Crimea, and parts of Russia were among the top offenders, lit up like beacons in the 1.4 GHz band. The red blobs on the map represented areas where SMAP picked up strong radio frequency interference – jamming, spoofing, or some kind of high-power EW emission.

What's remarkable about this phenomenon is that it's not just about jamming drones or disrupting military communications. When you consider the scale and intent behind these emissions, it becomes clear that we're dealing with something more sinister. The 1.4 GHz band isn't just a harmless frequency; it's also adjacent to some very useful real-world military signals.

Disrupting drone command and control links can have devastating consequences in modern conflicts. Jamming L-band signals means blinding drones, degrading targeting, and cutting off ISR (intelligence, surveillance, and reconnaissance). This isn't accidental; it's deliberate. The international treaties that regulate this spectrum don't apply when lives are on the line.

The cities of Dnipro, Simferopol, and Kryvyi Rih in Ukraine took top honors in this game of electromagnetic warfare. Their brightness temperatures soared past 370K, solidifying their positions as hotspots for radio frequency interference. No need for captions when the spectrum speaks for itself.

This is all open source. I didn't use any special tools or access restricted data feeds. Just a climate satellite, some Python programming, and a bit of time. The result? A map of electromagnetic warfare happening in real-time over Ukraine, Crimea, and parts of Russia.

Data Source: NASA SMAP L1B_TB

Code + Data: github.com/radioandnukes/SMAP-RFI-Mapper

Made by: Nuke's

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