Hey there, fellow radio enthusiasts! If you’ve ever wanted to capture high-resolution weather images straight from space, the Russian Meteor-M2 satellites (like Meteor-M2-3 and M2-4) are your ticket. These polar-orbiting weather satellites beam down digital Low Rate Picture Transmission (LRPT) signals at 137 MHz, offering crisp imagery that blows the old NOAA APT signals out of the water. Meteor-M2 Satellites
Russian Meteor-M2 satellites (launched 2014–2024) are a series of polar-orbiting meteorological spacecraft operated by Roscosmos/Roshydromet to monitor global weather, climate, ice conditions, and ozone levels.
I’ve been tinkering with this setup for a while, and let me tell you, seeing those vibrant Earth images pop up on your screen is worth every bit of effort. Here’s my step-by-step guide to getting your own Meteor-M2 LRPT receiving station up and running, written from one hobbyist to another.
Why Meteor-M2 Satellites?
Before we dive into the gear and setup, let’s talk about why these satellites are so cool. The Meteor-M2 Satellites series, including the active M2-3 (launched June 2023) and M2-4, transmit digital LRPT signals at 137.1 or 137.9 MHz. Unlike the grainy, analog NOAA APT images, LRPT delivers 1 km/pixel resolution with six spectral bands, capturing everything from visible light to infrared. These images are perfect for tracking cloud cover, sea temperatures, or just marveling at Earth’s beauty. However, M2-3 has a tricky antenna issue that causes signal fading, so we’ll cover how to work around that too.
What You’ll Need
Here’s the gear I use to pull this off. You don’t need to break the bank, but each piece is important for a solid setup:
- Antenna: A V-dipole or Quadrifilar Helix (QFH) antenna tuned for 137 MHz. I started with a homemade V-dipole using copper rods—it’s cheap and effective. If you’re chasing M2-3, a V-dipole is better than a QFH because you can adjust its orientation to compensate for the satellite’s wonky antenna. A QFH works great for M2-4, though, since it’s omnidirectional and forgiving for beginners.
- Receiver: An RTL-SDR dongle (like the RTL-SDR Blog V3, ~$30) is perfect for this. It’s affordable and handles the 150 kHz bandwidth needed for LRPT’s QPSK signal. I’ve also tested a Funcube Dongle Pro+, which works well but is pricier.
- Low-Noise Amplifier (LNA): A Sawbird or similar LNA with a 137 MHz filter boosts weak signals and cuts interference from nearby FM stations. Trust me, if you’re in a city, this is a game-changer.
- Coaxial Cable: RG-58 or better to connect your antenna to the SDR. Keep it as short as possible to minimize signal loss.
- Computer: A Windows or Linux machine (even an old laptop works). I run mine on a Windows 10 micro PC with 4 GB RAM, which handles everything fine.
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Software:
- SatDump: The easiest all-in-one tool for receiving and decoding LRPT signals. It’s available for Windows, Linux, and even Android (though the Android UI can be finicky).
- Orbitron or Look4Sat: For tracking satellite passes. Orbitron is great for Windows, while Look4Sat is handy on Android for predicting AOS (Acquisition of Signal) and LOS (Loss of Signal).
- Optional: SDR# with the Meteor Demodulator plugin and M2_LRPT_Decoder for a more manual setup. I’ll focus on SatDump since it’s simpler, but I’ll mention the SDR# alternative later.
Meteor-M2 Satellites – Step-by-Step Setup Guide
Alright, let’s get to the fun part—setting it all up. I learned this through trial and error, so I’ll share what worked for me and what to avoid.
1. Build or Set Up Your Antenna
I started with a V-dipole because it’s dirt-cheap and easy to make. Cut two copper rods to about 20 inches each (for 137 MHz), mount them on a non-metallic pole at a 120-degree angle, and connect them to your coax. Place it outside with a clear view of the sky—rooftops or balconies work great. If you’re targeting M2-3, be ready to adjust the antenna’s orientation during the pass to catch the signal as it fades in and out due to the satellite’s misaligned antenna. For M2-4, a QFH is more forgiving since its signal is steadier. Pro tip: If you’re in an urban area, add a 137 MHz band-pass filter to block FM interference.
2. Install and Configure Your SDR
Plug your RTL-SDR into your computer and connect it to the antenna via the LNA. Install the drivers (Zadig on Windows works well). Test it with SDR# to make sure it’s picking up signals around 137 MHz. You should see some noise or faint signals on the waterfall. Don’t use RTL AGC or Tuner AGC—they’re designed for wide signals like DVB-T and can mess up the narrow LRPT signal by applying too much gain. Set the gain manually to around 25-30 dB for starters.
3. Track Satellite Passes
Download Orbitron (Windows) or use Look4Sat (Android) to predict when M2-3 or M2-4 will pass over your location. M2-3 transmits at 137.9 MHz (primary) or 137.1 MHz (backup), while M2-4 uses 137.9 MHz in 72k mode. Check pass predictions for elevation above 20 degrees for the best signal. Orbitron can also integrate with SDR# for automatic frequency tuning, but we’ll stick with manual for now. Note the AOS and LOS times, and be ready to start receiving a few minutes early.
4. Set Up SatDump
SatDump is a lifesaver because it handles recording, demodulation, and decoding in one go, unlike the older SDR# + plugin stack. Download the latest release from the SatDump GitHub (Windows or Linux binaries are on the Releases page). Here’s how to configure it:
- Open SatDump and go to the Processing panel.
- Search for “METEOR M2-x LRPT 72k” and select it. If M2-4 is in 80k mode (check recent amateur radio forums for updates), select “METEOR M2-x LRPT 80k” instead.
- Check the DC Blocking box to reduce noise.
- Set Primary frequency to 137.9 MHz and Backup to 137.1 MHz.
- In the Input file field, select your SDR device (e.g., RTL-SDR).
- Choose an Output directory for the decoded images.
- In Input Level, select “soft” for M2-3 or “cadu” if processing a .cadu file from a previous recording.
- Hit Start when the satellite is in view.
SatDump will record the baseband IQ data and decode it into images. You’ll see the images in the Viewer tab, where you can add cool overlays like shorelines or city markers.
5. Monitor and Adjust
Watch the SatDump waterfall for the LRPT signal—it’ll look like a wide, blocky band around 137.9 MHz. For M2-3, the signal may jump due to the antenna issue, so tweak your V-dipole’s position if it fades. You’re aiming for a signal-to-noise ratio (SNR) of at least 5-6 dB to lock onto the QPSK signal. If the signal doesn’t sync, double-check the frequency and try 80k mode. Never use Doppler correction (like Orbitron’s transponder feature) as it messes with the demodulator’s Costas loop, causing data loss.
6. Process and Enjoy Your Images
Once the pass is over, SatDump saves greyscale images for each spectral band (e.g., 0.5-0.7 µm for visible, 1.6-1.8 µm for infrared). You can combine these in the Viewer tab to create RGB composites (like RGB123 for daylight). If the colors look off (blue snow, anyone?), use a tool like MeteorGIS to apply a “Green land” color scheme for a more natural look. MeteorGIS also fixes pesky dark bands caused by M2-3’s buffer issues. Save your high-res images and share them with the amateur satellite community!
Alternative Setup with SDR# and Plugins
If you prefer a hands-on approach, you can use SDR# with the Meteor Demodulator plugin and M2_LRPT_Decoder (version 59 or higher).
This is more complex but gives you fine control:
- Install SDR# and the Meteor Demodulator plugin.
- Set the modulation to WFM, bandwidth to 125 kHz, and center frequency to 137.9 MHz.
- Use Orbitron with the DDE plugin to track the satellite and auto-tune SDR#.
- Configure the Meteor Demodulator to output a .s file (QPSK symbols).
- Process the .s file in M2_LRPT_Decoder, selecting 72k or 80k mode. Set “rgb=123.jpg” for daylight images.
- Use MeteorGIS for final processing and georeferencing.
This method is powerful but requires juggling multiple programs. SatDump is easier for beginners, so I recommend starting there.
Troubleshooting Tips
- Weak Signal: If your SNR is below 5 dB, boost the LNA gain or move your antenna to a clearer spot. M2-3’s signal is weaker due to its antenna issue.
- No Signal on Waterfall: Double-check the frequency (137.9 or 137.1 MHz) and pass time. M2-4 may be off; check r/amateursatellites for status updates.
- Black Bands in Images: Common with M2-3 due to buffer overflow. MeteorGIS can patch these up.
- Constellation Issues: If the QPSK constellation in SatDump or SDR# looks like a hazy blob instead of four distinct dots, adjust gain or try a different antenna orientation.
With a $30 SDR, a homemade antenna, and free software like SatDump, you can pull down stunning images that rival professional weather stations. Just watch out for M2-3’s quirky antenna and stay flexible with your setup. Got questions or want to share your first capture? Drop a comment below—I’d love to hear how it goes!
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