Amateur ground station DC8PAT (locator JN58ua) for the geostationary weather satellite Elektro-L No.3 (14.5° W), LRIT downlink at 1691 MHz. The station runs unattended: it decodes every transmission, logs the signal level and publishes the images on this page.

Live: band level and transmissions

Signal level in a 300 kHz window around the carrier, in dB over the median of the 2.4 MHz span, 10 s resolution. Dashed line: 4.4 dB, the steady level needed for a clean decode. The bar below the plot shows each transmission: green = all 30 image segments clean, orange = damaged segments, grey = precursor at xx:12 UTC, blue = next scheduled transmissions. The countdown runs to the expected start of the next transmission; day transmissions start 20–60 s after xx:42, night transmissions within a few seconds.

Live: waterfall

OpenWebRX on 1691.0 MHz, 2.4 MHz span. Between transmissions only noise and local interference lines are visible. If the frame does not load, open sdr.nolle.engineering directly.

Images of the last 24 hours

One row per transmission, newest first; each row holds every product of that scan. Every product SatDump produced is shown; products built from a channel with missing or corrupted segments are marked damaged and name the affected segments. Visible-light products are left out at night. New images appear a few minutes after the transmission ends. Click an image for the full 2784 × 2784 pixel original. Times are scan times in UTC.

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Station

Component	Details
Antenna	Offset dish, reflector 97 × 87 cm, effective aperture ≈0.85 m, ≈21 dBi, beamwidth ≈14° at 1691 MHz
Pointing	Azimuth 213.5° true, elevation 29.3° (fixed, no rotator)
Feed	3-turn helix, LHCP (L-Band WX HRPT feed), in the LNB holder with a printed adapter, phase centre 20 mm behind the standard LNB position
LNA	SAW-filtered LNA for the 1.7 GHz band at the feed, powered via bias-T
Receiver	Nooelec NESDR SMArTee (RTL-SDR, TCXO), 1691.0 MHz, 2.4 MS/s, gain 49.6 dB
Computer	Raspberry Pi 4
Software	SatDump 1.2.2 (elektro_lrit pipeline), OpenWebRX (public waterfall)
Monitoring	Band level and transmission results to InfluxDB, shown in Grafana (live panel above)

Downlink

Parameter	Value
Satellite	Elektro-L No.3, geostationary, 14.5° W
Frequency / polarisation	1691.0 MHz, RHCP (feed at the dish focus is LHCP: the reflector reverses the sense)
Occupied bandwidth	≈±230 kHz
Transmission schedule (UTC)	Every 3 h from 00:42 (00:42, 03:42 … 21:42), carrying the xx:30 scan; 5–10 min each. Night transmissions start within 1–4 s of xx:42:00, day transmissions (09:42, 12:42, 15:42) 20–60 s later
Precursor	Transmission at xx:12 UTC (start within 1–5 s), ≈4 min, wider than LRIT, not decoded (used as pointing beacon)
Channels	0.6, 0.7, 0.9 µm (visible/near IR, daylight); 3.8, 10.7 µm (IR, day and night)
Image	Full disk, 2784 × 2784 px per channel, 4.0 km/px at the sub-satellite point
Segments	6 per channel, 30 per transmission; order 3.8, 10.7, 0.9, 0.7, 0.6 µm

Performance

Measurement	Value
Band level between transmissions	0.6–0.8 dB
Band level during a transmission (since final pointing, 13.11.2026)	4.75 dB median
Level for an error-free decode	≥4.4 dB steady
Precursor at xx:12	≈1.5 dB

Operating notes

• LRIT is not continuous: the satellite sends eight transmissions a day. Pointing and tests only make sense during a transmission or the xx:12 precursor.
• Any movement of the dish during a transmission damages the segments received in that time.
• SatDump 1.2.2 writes a channel only when all six segments are in and does not separate scans; it is restarted after each transmission.
• A short buffer in the sample splitter silently drops samples when a client falls behind; this looks like a weak signal. nmux runs with a 7 s buffer.
• Several RTL-SDRs on one USB hub dropped out repeatedly; the SDR is on a Pi USB port directly.
• A dead LNA looks like bad pointing. Check: switching the bias-T must raise the noise floor by several dB.
• Damaged transmissions are archived with the decoder log.

Signals at 1691 MHz

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Receiving Elektro-L3, L4 or L5?

If you receive Elektro-L No.3, No.4 or No.5 yourself, please get in touch: info@nolle.engineering. We are interested in your setup (dish, feed, LNA, SDR), signal levels, transmission times you observe and the decoder settings that work for you, and we are happy to share our logs and settings in return. Markus OE3HWC in Austria receives Elektro-L3 with our feed on a 1 m dish (see his first L-band images from OE3HWC in Austria).

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Build your own

The feed on this station is our L-Band WX HRPT feed. For other dishes or frequencies, ask us.

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