Tutorial Weather satellite images

Pictures grow line by line while the satellite passes overhead.

Which satellites

Mode	Where	You need
Meteor-M LRPT	Meteor-M N2-3 / N2-4 on 137.100 / 137.900 MHz	an antenna for 137 MHz and a radio that tunes it
GOES HRIT	GOES-16 / 18 / 19 on 1694.1 MHz	a dish (about 1 m, or a grid antenna) with an LNA and filter at the feed
Elektro-L	Elektro-L N3 / N4 / N5 around 1691 MHz	a dish with an LNA
HRPT / AHRPT	MetOp-B / -C AHRPT on 1701.3 MHz	a dish (1 m or more) that follows the satellite, an LNA at the feed and a fast radio (4 Msps or more; not an RTL-SDR)

NOAA's own HRPT is listed in HRPT / AHRPT, but NOAA-15, 18 and 19 are retired.

Steps for Meteor-M LRPT

1. Set your position (setup wizard or the map) so passes can be computed.
2. Open View > Passes, the satellite pass planner. It uses current orbital data (TLE): download a list, add your own custom TLE source, or use the Keplerpass button. See Privacy for which servers those are.
3. Choose Meteor-M LRPT (group Weather and science). The default is 137.9 MHz.
4. Let the pass planner start the receiver at AOS (acquisition of signal). It follows the Doppler shift, and the carrier hand-over tracks about ±3.5 kHz of it (0.2.6).
5. Watch the picture grow line by line: channels 1 to 6 and a colour composite (123 by day, 125 at night). Press Save PNG; there are contrast stretch, thermal colours, brighten and auto-save options (0.2.6).
6. The pass planner can also record the radio's IQ during the pass, as Record IQ does.

Notes

• Real frames pass Reed-Solomon since 0.2.5 (issue 79); GitHub issue 79 (Meteor M2-3 LRPT) is still open, so recordings of real passes are welcome.
• A rotator can point a dish: see antenna rotator.