GEO-KOMPSAT-2A is a Korean earth observation satellite that transmits weather satellite images and other meteorological data on L-Band(1692.14MHz). It has a considerably large footprint and covers Asia, Australia, New Zealand, and eastern Russia. Its LRIT transmission can be easily received from Sri Lanka with a small Ku band dish and an SDR. Although it also transmits HRIT on L-Band(1695.4Mhz), a larger dish is required to receive it successfully. There is a very comprehensive guide written by @sam210723 on his website & another one on RTL-SDR-Blog which covers everything you need to know about how to receive the GK-2A LRIT downlink.
Hardware Setup
An RTL-SDR V3 dongle can be used to receive the GK-2A LRIT downlink and Sawbird+Goes is a good LNA choice. Although a linear feed is preferred for receiving it, When I pointed my existing HRPT dish setup (with an LHCP helical feed and a Sawbird+Goes) at it, I was able to get a good signal.
Goesrecv & Xrit-rx
So I installed "goesrecv" and "xrit-rx" on a Raspberry Pi-4, Edited the goesrecv configuration file for the RTL-SDR V3 dongle, Downloaded "EncryptionKeyMessage_001F2904C905.bin" from the NMSC page, Decrypted it, Configured xrit-rx to work with "EncryptionKeyMessage.bin", Execute "goesrecv -v -i 1 -c goesrecv.conf" in the goesrecv directory to start it, Opened a new terminal, navigated to xrit-rx directory and execute "python3 xrit-rx.py" to start it as well. Then I could see the image reception started.
I visited 127.0.0.1:1692 on a web browser to see the xrit-rx dashboard and sure enough, I could see the LRIT timetable and real-time image reception data displayed.
I also set up the goesrecv monitor on my windows PC later according to the guide and tweaked my dish alignment to get the maximum SNR.
Post Processing
Sanchez & GIMP can be used to add false color, underlays & overlays, and time stamps to GK-2A images. Since it transmits a full disk image every 10 minutes, a total of 144 full disk images every day, it's possible to make smooth animations from them. Documentation on Sanchez & GIMP plug-ins can be found on their respective websites.
Additional Data
In addition to full disk images, it transmits weather charts, regional and global wave models, sea temperature charts, weather forecast reports, and much more...
Both goesrecv & xrit-rx were very well optimized so this setup can be run 24x7 without worrying about overeating or thermal throttling the Raspberry Pi
