METEOR

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METEOR pictures (LRPT)

From 20.82, in beta. SatMe decodes the pictures the Russian weather satellites METEOR-M2-3 and METEOR-M2-4 send on 137.9 MHz (sometimes 137.1 MHz), straight from an RTL-SDR dongle plugged into the phone: a colour picture by day and an infrared one, a strip about 2,800 km wide along the pass.

Reception under way, with its preview · the pass decoded · the pictures received.

A whole METEOR-M2-4 pass (5 March 2026, Alaska and the Bering Sea), decoded by SatMe: colour on the left, infrared on the right.

Beta. Decoding is checked against the recording of a real METEOR-M2-4 pass (6,076 frames, 8 lost, the whole pass in pictures; two minutes of signal decoded in 14 s on a phone). It has not yet been tried live. The page says so too.

What you need

• An RTL-SDR dongle (RTL2832U) on the phone, through a USB-OTG adapter — see Extensions.
• A 137 MHz antenna: QFH, turnstile, V-dipole… The signal is 120 kHz wide and digital: a radio's audio output will not do.
• The satellite METEOR-M2-3 or M2-4 in your list (Settings › Satellites). The old METEOR-M2 (2014) and M2-2 send nothing any more: SatMe leaves them out.

Live

1. Open the page of METEOR-M2-3 or M2-4 a little before AOS. Under the compass, in place of SSTV, the METEOR pictures (LRPT) card says what is missing (the dongle, the antenna) or offers Receive the pictures.
2. Press it: the dongle tunes the LRPT 72 kbps channel on 137.900 MHz (137.100 MHz when that is the one listed) and follows the Doppler. Sound, MP3 recording and SSTV decoding stay off: there is nothing to hear. Starting the dongle from its own card (▶) does the same.
3. The card shows the search, then Locked: N lines, N frames and the picture building up; ■ stops. One tap opens the METEOR pictures page (also in the ⋮ menu).
4. When the dongle stops, the pictures are written: colour (channels 2-2-1: land green-brown, sea dark blue, snow and clouds white) and infrared (day and night). North is up: a pass going north is turned half round. Save now writes them mid-pass.

On the page: whether the decoder is locked, the lines and frames received, the symbol quality in dB (above about 6 dB the frames come through), the carrier offset found, the channels seen. If the phone falls behind, the blocks dropped are counted and show as a black band.

Which transmitter

The METEOR lists on SatNOGS are long: LRPT at 72 and 80 kbps on 137.1, 137.9 and 137.9125 MHz, an "IQ recording" entry, HRPT on 1.7 GHz, L, S and X bands. SatMe decodes the LRPT 72 kbps: on a METEOR page it is the transmitter chosen at first, and the dongle always goes to it, whatever is selected. The 80 kbps variant, which the satellites sometimes use, is not decoded yet: on such a day SatMe will not lock even on a good signal.

Automatic

Start by itself on every pass: a minute before each METEOR-M2-3 or M2-4 pass, the dongle starts on the satellite; it stops 30 s after LOS and the pictures are written. The page shows the next pass.

• The dongle must be plugged in and SatMe open, as for any SDR reception.
• A reception started by hand is never interrupted.

Decoding a recording

Pick a file: a WAV file of the raw signal — I/Q on two channels, 32-bit float, 16 or 8 bits, 150 to 3,000 kS/s. It is read where it lies, not copied (a pass is about 1 GB). The date in the file name (20260305_0021, 2026-03-05…) becomes the picture's date. A recording from elsewhere gets neither your locator nor your callsign.

The pictures

They are in the gallery of the METEOR page: share, save, delete. Like SSTV and NOAA pictures, they are also copied to the export folder chosen for the recordings, when there is one.

• A scan missing in one channel only is filled from its neighbours; longer gaps stay black.
• In colour, a place where one of the two channels is missing stays black rather than taking a false colour.
• Coastlines and borders (switch on the METEOR page, on by default): drawn from the satellite's orbit, coasts in yellow, borders in white, on the preview and the saved pictures. The satellite's orbital elements must be up to date: with old ones, the lines slide along the track (seven-month-old elements put them about 140 km off). For a recording, the satellite's name in the file name (meteor-m2-4…) finds its elements, and the orbit then also says whether the pass went north or south.

Under the hood

LRPT is offset QPSK at 72,000 symbols per second, with a convolutional code, Reed-Solomon and CCSDS packets; the imager's lines arrive as 8 × 8 blocks compressed much like a JPEG. SatMe decodes all of it on the phone, in its own code: no server, no network.