A Faster Method for Decoding Meteor M2 Weather Satellite Images
Over on YouTube user max30max31 aka IZ5RZR has uploaded a video that shows a faster method for decoding Meteor M2 weather satellite images on a Windows system. The Meteor-M N2 is a Russian weather satellite that transmits images using the LRPT protocol at around 137.1 MHz with can be received with an RTL-SDR. Compared to NOAA satellite APT images, LRPT images are much higher in resolution.
Normally, decoding Meteor M2 LRPT images requires a post processing step which involves the use of Audacity, an audio editing suite to reduce the recorded IQ files sample rate. However, with the recently released decimation SDR# drivers the Audacity step can be avoided by using a an appropriate decimation factor (8 at 1.024 MSPS) when recording the LRPT signals IQ data.
Post processing still involves the use of the Lrptrx.exe software, Oleg’s LRPToffLineDecoder to produce the image and SmoothMeteor to remove distortion from the image..
Since switching to the decimation driver my pictures of M2 have been worse, using 900k and reducing rate in Audacity is all that works reliably. For me, recording at 250k is a bad idea because I am so near FM transmitters the baseband is wrecked with images.
If you have a weaker signal reception changing the samplerate and/or using decimation with the ‘new’ driver can result in more white lines with processing the final image in LrptOfflineDecoder.
The faster method does not weight for the picture quality then 😉
But YMMV offcourse..
Only by placing the sample rate at 0.25 msps and recording the baseband can be decoded with lrpt.exe. Simply.