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I've reached some geostationary and orbiting weather satellites with Software-Defined Radio (SDR) in the past. I'd love to try and snag some signals from these.

by l00sed 6y ago

I've reached some geostationary and orbiting weather satellites with Software-Defined Radio (SDR) in the past. I'd love to try and snag some signals from these... Anyone know of a more formal scientific write-up on these to find the frequency/modulation?

gpm 6y ago
The FCC filings are probably your best bet, 95% of the technical details we know are from them (92% of statistics are made up). I'm not sure if they contain enough information for you though. There are links here: https://old.reddit.com/r/Starlink/wiki/index#wiki_-_what_frequency_bands_does_it_use.3F https://old.reddit.com/r/Starlink/wiki/index#wiki_-_what_fre...
londons_explore 6y ago
The frequency bands and modulation types are available from the FCC. The data will probably be encrypted, but I think theres a good chance you might be able to get some metadata.
wmf 6y ago
https://fcc.report/IBFS/SAT-LOA-20161115-00118/1158350 https://fcc.report/IBFS/SAT-LOA-20161115-00118/1158350
nullpage 6y ago
From what sparse info I can find, it appears ground > sat > ground comms will be encrypted in some fashion so listening with an SDR and doing anything meaningful with the data might be hard, but I'm curious if there will be opportunities for it to be abused for anonymous downlink connections like the Turla spyware group used to do (https://arstechnica.com/information-technology/2015/09/how-highly-advanced-hackers-abused-satellites-to-stay-under-the-radar/ https://arstechnica.com/information-technology/2015/09/how-h...)
mrspeaker 6y ago
I have an SDR module and have played around listening to things (and having a blast doing it) but nothing like that! That sounds really cool. Do you have any resources you could point?
- l00sed 6y ago
  It's really incredible what the consumer RTL-SDR can do for the price. I watched this user's video (https://www.youtube.com/watch?v=cjClTnZ4Xh4&vl=en https://www.youtube.com/watch?v=cjClTnZ4Xh4&vl=en) and went down the rabbithole. Made my own dipole for an art exhibit: https://l-o-o-s-e-d.net/signs-of-life https://l-o-o-s-e-d.net/signs-of-life
jandrese 6y ago
A RTL-SDR with whatever antenna you whipped up to listen to NOAA sats is not going to have enough link margin to tune in a SpaceX transmission. IIRC the example user terminal SpaceX demoed ages ago is a phased array hooked up to a fairly beefy modem.
l00sed 6y ago
It seems that all the frequencies are 10GHz+ which is way past the range of most readily-available SDR dongles... Probably not feasible ATM.
- xxpor 6y ago
  You can semi-easily get transverters for those frequencies.
  - ckocagil 6y ago
    Also 10 GHz is possible with some knowledge and effort. See the hams on Youtube reaching QO-100.
- person_of_color 6y ago
  All that matters is the bandwidth. You could mix it down to a lower frequency.

by l00sed 6y ago

gpm 6y ago

The FCC filings are probably your best bet, 95% of the technical details we know are from them (92% of statistics are made up). I'm not sure if they contain enough information for you though. There are links here: https://old.reddit.com/r/Starlink/wiki/index#wiki_-_what_frequency_bands_does_it_use.3F https://old.reddit.com/r/Starlink/wiki/index#wiki_-_what_fre...

londons_explore 6y ago

The frequency bands and modulation types are available from the FCC. The data will probably be encrypted, but I think theres a good chance you might be able to get some metadata.

wmf 6y ago

https://fcc.report/IBFS/SAT-LOA-20161115-00118/1158350 https://fcc.report/IBFS/SAT-LOA-20161115-00118/1158350

nullpage 6y ago

From what sparse info I can find, it appears ground > sat > ground comms will be encrypted in some fashion so listening with an SDR and doing anything meaningful with the data might be hard, but I'm curious if there will be opportunities for it to be abused for anonymous downlink connections like the Turla spyware group used to do (https://arstechnica.com/information-technology/2015/09/how-highly-advanced-hackers-abused-satellites-to-stay-under-the-radar/ https://arstechnica.com/information-technology/2015/09/how-h...)

mrspeaker 6y ago

I have an SDR module and have played around listening to things (and having a blast doing it) but nothing like that! That sounds really cool. Do you have any resources you could point?

l00sed 6y ago
It's really incredible what the consumer RTL-SDR can do for the price. I watched this user's video (https://www.youtube.com/watch?v=cjClTnZ4Xh4&vl=en https://www.youtube.com/watch?v=cjClTnZ4Xh4&vl=en) and went down the rabbithole. Made my own dipole for an art exhibit: https://l-o-o-s-e-d.net/signs-of-life https://l-o-o-s-e-d.net/signs-of-life

jandrese 6y ago

A RTL-SDR with whatever antenna you whipped up to listen to NOAA sats is not going to have enough link margin to tune in a SpaceX transmission. IIRC the example user terminal SpaceX demoed ages ago is a phased array hooked up to a fairly beefy modem.

l00sed 6y ago

It seems that all the frequencies are 10GHz+ which is way past the range of most readily-available SDR dongles... Probably not feasible ATM.

xxpor 6y ago
You can semi-easily get transverters for those frequencies.
- ckocagil 6y ago
  Also 10 GHz is possible with some knowledge and effort. See the hams on Youtube reaching QO-100.
person_of_color 6y ago
All that matters is the bandwidth. You could mix it down to a lower frequency.