Weather Satellite Decoder

ALPHA: Weather Satellite capture is experimental and may fail depending on SatDump version, SDR driver support, and pass conditions.

Receive and decode Meteor LRPT weather imagery. Uses SatDump for live SDR capture and image processing, and also shows Meteor imagery produced by the ground-station scheduler.

Getting Started

What are Meteor satellites?

Russia's Meteor-M2-3 and Meteor-M2-4 are polar-orbiting weather satellites that continuously transmit real-time color imagery (clouds, land, sea) at 137.900 MHz using the LRPT digital format. Unlike old analog NOAA APT, LRPT produces sharp, full-color images.

They orbit ~830 km high, circling the Earth every ~100 minutes in a near-polar sun-synchronous orbit. From any location, you'll typically get 4–8 usable passes per day, each lasting 8–15 minutes as the satellite crosses your sky.

Step-by-step

Set your location — Enter your lat/lon in the strip bar above (or click GPS). This is required for pass predictions.
Check upcoming passes — The pass list shows when each satellite will be overhead. Higher max elevation = better signal. Passes above 30° are "good", above 60° are "excellent".
Prepare your antenna — You need a 137 MHz antenna outdoors with clear sky (see Antenna Guide below). A $5 V-dipole works for high passes.
Click Capture on a pass card when it's about to start, or enable AUTO to let the scheduler capture automatically.
Wait for images — SatDump will tune, lock the signal, and decode. Decoded images appear in the gallery after the pass completes.

When to look

Best passes: When the satellite is high overhead (>30° elevation). The countdown timer shows the next one.
Day vs night: Daytime passes produce visible-light imagery. Night passes still work but only produce infrared/thermal images.
Both satellites share 137.9 MHz so they won't transmit at the same time. You'll see separate pass predictions for each.
Pass direction: Meteor satellites travel roughly north→south or south→north. The pass cards show the exact rise/set direction.

What you need

SDR receiver	RTL-SDR V3/V4 ($25-35)
Antenna	137 MHz V-dipole ($5 DIY) or QFH ($20-30)
LNA (optional)	137 MHz filtered, at antenna ($15-25)
Location	Outdoors, clear sky view
No hardware?	Use Load Demo Data below to explore the UI

Satellite

Select Satellite

Gain (dB)

Reduce if decoding fails on strong passes (ADC saturation).

Bias-T (power LNA)

Antenna Guide ▼

137 MHz band — your stock SDR antenna will NOT work.

Weather satellites transmit at 137.1–137.9 MHz. The quarter-wave at this frequency is ~53 cm, far longer than the small telescopic antenna shipped with most SDRs (tuned for ~1 GHz). You need a purpose-built antenna.

V-Dipole (Easiest — ~$5)

   coax to SDR
       |
    ===+===  feed point
   /       \
  /  120    \
 /           \
/     deg     \
53.4cm    53.4cm

Element length: 53.4 cm each (quarter wavelength at 137 MHz)
Angle: 120° between elements (not 180°)
Material: Any stiff wire, coat hanger, or copper rod
Orientation: Lay flat or tilt 30° toward expected pass direction
Polarization: The 120° angle gives partial RHCP match to satellite signal
Connection: Solder elements to coax center + shield, connect to SDR via SMA

Best starter antenna. Good enough for a clean Meteor LRPT pass when the satellite gets high overhead.

Turnstile / Crossed Dipole (~$10-15)

       53.4cm
    <--------->
    ====+====  dipole 1
        |
    ====+====  dipole 2
    <--------->
     90 deg rotated
     + reflector below

Elements: Two crossed dipoles, each 53.4 cm per side (4 elements total)
Angle: 90° between the two dipole pairs
Phasing: Feed dipole 2 with a 90° delay (quarter-wave coax section ~37 cm of RG-58)
Reflector: Place ~52 cm below elements (ground plane or wire grid)
Polarization: Circular (RHCP) — matches satellite transmission

Better than V-dipole. The reflector rejects ground noise and the RHCP phasing matches the satellite signal.

QFH — Quadrifilar Helix (Best — ~$20-30)

     ___
    /   \   two helix loops
   |  |  |  twisted 90 deg
   |  |  |  around a mast
    \___/
      |
    coax

Design: Two bifilar helical loops, offset 90°
Material: Copper pipe (10mm), copper wire, or coax outer shield
Total height: ~46 cm (for 137 MHz)
Loop dimensions: Use a QFH calculator for exact bending measurements
Polarization: True RHCP omnidirectional — ideal for overhead satellite passes
Gain pattern: Hemispherical upward coverage, rejects ground interference

Gold standard for weather satellite reception. No tracking needed — covers the whole sky.

Placement & LNA

Location: OUTDOORS with clear sky view is critical. Roof/balcony/open field.
Height: Higher is better but not critical — clear horizon line matters more
Antenna up: Point the antenna straight UP (zenith) for best overhead coverage
Avoid: Metal roofs, power lines, buildings blocking the sky
Coax length: Keep short (<10m). Signal loss at 137 MHz is ~3 dB per 10m of RG-58
LNA: Mount at the antenna feed point, NOT at the SDR end. Recommended: a low-noise 137 MHz filtered LNA near the antenna feed point
Bias-T: Enable the Bias-T checkbox above if your LNA is powered via the coax from the SDR

Quick Reference

Wavelength (137 MHz)	218.8 cm
Quarter wave (element length)	53.4 cm
Best pass elevation	> 30°
Typical pass duration	10-15 min
Polarization	RHCP
Meteor (LRPT) bandwidth	~140 kHz

Offline Decode (IQ File) ▼

Decode a pre-recorded Meteor IQ baseband file without SDR hardware. You need an actual .raw, .sigmf-data, or .wav recording of a Meteor pass.

Where to get a test file:

Record one yourself with rtl_sdr -f 137900000 -s 2400000 meteor.raw during a pass
Download samples from SigID Wiki or community forums
Place the file in data/weather_sat/ on the server

Satellite

File Path (server-side, relative to app root)

Sample Rate

Auto-Scheduler

Automatically capture satellite passes based on predictions. Set your location above and toggle AUTO in the strip bar.

Enable Auto-Capture

Disabled

Debug / Test

Load sample pass data and console output to test the UI without an SDR or live satellite pass.

Resources

SatDump Documentation Meteor Reception Guide