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Thought it would be fun to receive the downlinks from Lightsail 2 with an SDR. Does anyone have any info on frequencies/modulation modes being used, above and

Thought it would be fun to receive the downlinks from Lightsail 2 with an SDR. Does anyone have any info on frequencies/modulation modes being used, above and beyond the Morse code beacon [1] at UHF? [1] http://www.planetary.org/blogs/jason-davis/2016/20160609-lightsail-2-morse-code.html http://www.planetary.org/blogs/jason-davis/2016/20160609-lig...

kawfey 7y ago
The FCC license registration [0] contains some interesting information. - Experimental radio service call sign WM9XPA - Using an Icom IC-821C Transceiver [1], a twenty-something year old VHF/UHF ham radio...wow for a $7M project couldn't they have spent more on a radio? Well, maybe not, I'll get to that in a minute. - Ground station is in the middle of nowhere? I think something with the Lat-Lon might be off if they mention West Lafayette, IN as the city (Purdue is located here). - The satellite's datalink is FSK on 437.025 MHz, designation 15K0F1D, which is a standard 15kHz wide FM modulated FSK signal. The signal's parameters are not known from the registration but I googled some more and found their FAQ which links to their protocol description [2]. In a nutshell it's run-of-the-mill AX.25 at 9600baud using a simple encoding for various parameters. You could decode this easily with an SDR and Direwolf [3] or GNURadio. This is why they can use the low-cost ham radio. I'm also willing to bet they'll be leveraging submissions from amateur radio operators and the automated SATNOGS network [4] to harvest more data. [0] https://fcc.report/ELS/The-Planetary-Society/1029-EX-ST-2019 https://fcc.report/ELS/The-Planetary-Society/1029-EX-ST-2019 [1] http://www.rigpix.com/icom/ic821h.htm http://www.rigpix.com/icom/ic821h.htm [2] https://planetary.s3.amazonaws.com/projects/lightsail/manuals/ls2-beacon-info-v01.txt https://planetary.s3.amazonaws.com/projects/lightsail/manual... [3] https://github.com/wb2osz/direwolf/blob/dev/doc/README.md https://github.com/wb2osz/direwolf/blob/dev/doc/README.md [4] https://satnogs.org/ https://satnogs.org/
- JoeDaDude 7y ago
  Great info, thank you! I'll see if I can rig some of this up in GNU Radio. Thanks again! PS: Casual trivia. I used to own that Icom model radio ages ago, gave it to my father who used it for SWL.

kawfey 7y ago

The FCC license registration [0] contains some interesting information. - Experimental radio service call sign WM9XPA - Using an Icom IC-821C Transceiver [1], a twenty-something year old VHF/UHF ham radio...wow for a $7M project couldn't they have spent more on a radio? Well, maybe not, I'll get to that in a minute. - Ground station is in the middle of nowhere? I think something with the Lat-Lon might be off if they mention West Lafayette, IN as the city (Purdue is located here). - The satellite's datalink is FSK on 437.025 MHz, designation 15K0F1D, which is a standard 15kHz wide FM modulated FSK signal. The signal's parameters are not known from the registration but I googled some more and found their FAQ which links to their protocol description [2]. In a nutshell it's run-of-the-mill AX.25 at 9600baud using a simple encoding for various parameters. You could decode this easily with an SDR and Direwolf [3] or GNURadio. This is why they can use the low-cost ham radio. I'm also willing to bet they'll be leveraging submissions from amateur radio operators and the automated SATNOGS network [4] to harvest more data. [0] https://fcc.report/ELS/The-Planetary-Society/1029-EX-ST-2019 https://fcc.report/ELS/The-Planetary-Society/1029-EX-ST-2019 [1] http://www.rigpix.com/icom/ic821h.htm http://www.rigpix.com/icom/ic821h.htm [2] https://planetary.s3.amazonaws.com/projects/lightsail/manuals/ls2-beacon-info-v01.txt https://planetary.s3.amazonaws.com/projects/lightsail/manual... [3] https://github.com/wb2osz/direwolf/blob/dev/doc/README.md https://github.com/wb2osz/direwolf/blob/dev/doc/README.md [4] https://satnogs.org/ https://satnogs.org/

JoeDaDude 7y ago
Great info, thank you! I'll see if I can rig some of this up in GNU Radio. Thanks again! PS: Casual trivia. I used to own that Icom model radio ages ago, gave it to my father who used it for SWL.