sdr

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off grid weather station

915 MHz Forecast: Rolling Your Own Offline Weather Station

December 19, 2025 by 9 Comments

There are a lot of options for local weather stations; most of them, however, are sensors tied to a base station, often requiring an internet connection to access all features. [Vinnie] over at vinthewrench has published his exploration into an off-grid weather station revolving around a Raspberry Pi and an RTL-SDR for communications.

The weather station has several aspects to it. The main sensor package [Vinnie] settled on was the Ecowitt WS90, capable of measuring wind speed, wind direction, temperature, humidity, light, UVI, and rain amount. The WS90 communicates at 915 MHz, which can be read using the rtl_433 project. The WS90 is also available for purchase as a standalone sensor, allowing [Vinnie] to implement his own base station.

For the base station, [Vinnie] uses a weatherproof enclosure that houses a 12V battery with charger to act as a local UPS. This powers the brains of the operation: a Raspberry Pi. Hooked to the Pi is an RTL-SDR with a 915 MHz antenna. The Pi receives an update from the WS90 roughly every 5 seconds, which it can decode using the rtl_433 library. The Pi then turns that packet into structured JSON.

The JSON is fed into a weather model backend that handles keeping track of trends in the sensor data, as well as the health of the sensor station. The backend has an API that allows for a dashboard weather site for [Vinnie], no internet required.

Thanks, [Vinnie], for sending in your off-grid weather station project. Check out his site to read more about his process, and head over to the GitHub page to check out the technical details of his implementation. This is a great addition to some of the other DIY weather stations we’ve featured here.

2G Gone? Bring It Back Yourself!

October 6, 2025 by 25 Comments

Some parts of the world still have ample 2G coverage; for those of in North America, 2G is long gone and 3G has either faded into dusk or beginning its sunset. The legendary [dosdude1] shows us it need not be so, however: Building a Custom 2G GSM Cellular Base Station is not out of reach, if you are willing to pay for it. His latest videos show us how.

Before you start worrying about the FCC or its equivalents, the power here is low enough not to penetrate [dosdude]’s walls, but technically this does rely in flying under the radar. The key component is a Nuand BladeRF x40 full-duplex Software Defined Radio, which is a lovely bit of open-source hardware, but not exactly cheap. Aside from that, all you need is a half-decent PC (it at least needs USB-3.0 to communicate with the SDR, the “YateBTS”  software (which [dosdude1] promises to provide a setup guide for in a subsequent video) and a sim card reader. Plus some old phones, of course, which is rather the whole point of this exercise.

The 2G sunset, especially when followed by 3G, wiped out whole generations of handhelds — devices with unique industrial design and forgotten internet protocols that are worth remembering and keeping alive. By the end of the video, he has his own little network, with the phones able to call and text one another on the numbers he set up, and even (slowly) access the internet through the miniPC’s network connection.

Unlike most of the hacks we’ve featured from [dosdude1], you won’t even need a soldering iron, never mind a reflow oven for BGA. 

Continue reading “2G Gone? Bring It Back Yourself!” →

The Wow! signal represented as "6EQUJ5" with Jerry R. Ehman's handwritten comment.

Listening For The Next Wow! Signal With Low-Cost SDR

September 18, 2025 by 14 Comments

As you might expect, the University of Puerto Rico at Arecibo has a fascination with radio signals from space. While doing research into the legendary “Wow! Signal” detected back in 1977, they realized that the burst was so strong that a small DIY radio telescope would be able to pick it up using modern software-defined radio (SDR) technology.

This realization gave birth to the Wow@Home project, an effort to document both the hardware and software necessary to pick up a Wow! class signal from your own backyard. The University reasons that if they can get a bunch of volunteers to build and operate these radio telescopes, the resulting data could help identify the source of the Wow! Signal — which they believe could be the result of some rare astrophysical event and not the product of Little Green Men.

Ultimately, this isn’t much different from many of the SDR-based homebrew radio telescopes we’ve covered over the years — get a dish, hook your RTL-SDR up to it, add in the appropriate filters and amplifiers, and point it to the sky. Technically, you’re now a radio astronomer. Congratulations. In this case, you don’t even have to figure out how to motorize your dish, as they recommend just pointing the antenna at a fixed position and let the rotation of the Earth to the work — a similar trick to how the legendary Arecibo Observatory itself worked.