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LoRa has some ridiculous range with minimal use of power. Being able to bounce it off the moon may allow communication between a whole Earth hemisphere. At the

LoRa has some ridiculous range with minimal use of power. Being able to bounce it off the moon may allow communication between a whole Earth hemisphere. At the least, this allows beyond-horizon communication.

bigiain 5y ago
A personal messaging system for you and all your friends who have a 35m radio telescope dish in their backyards...
suyula 5y ago
They're bouncing them off the retroreflectors on the moon though, right? So that doesn't necessarily translate to being able to send messages to anywhere on the hemisphere.
- 7kay 5y ago
  No, the radio waves bounce off the moon's surface. The retroreflectors are not necessary for that, otherwise stuff like Earth-Venus-Earth bounces[1] would not be possible. [1]: https://amsat-dl.org/en/earth-venus-earth-experiment-of-amsat-dl-successful/ https://amsat-dl.org/en/earth-venus-earth-experiment-of-amsa...
7kay 5y ago
As others have already pointed out this exercise used a huge dish(a radio telescope[1]) and significant power. This is in no way an economically viable mode of communication. Using satellites in low earth orbit requires less power and a significantly smaller antenna. Putting LoRa on satellites has been done before, see e.g. [2]. [1]: https://en.wikipedia.org/wiki/Dwingeloo_Radio_Observatory https://en.wikipedia.org/wiki/Dwingeloo_Radio_Observatory [2]: https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=4657&context=smallsat https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=4...
karteum 5y ago
Well, here in that case they were using an approach that would be illegal by EU regulations (not sure about US) considering the EIRP limits :) And if you want real low-power long-range communications with the other side of the earth, you may be interested to have a look at WSPR https://en.wikipedia.org/wiki/WSPR_(amateur_radio_software) https://en.wikipedia.org/wiki/WSPR_(amateur_radio_software) !

bigiain 5y ago

A personal messaging system for you and all your friends who have a 35m radio telescope dish in their backyards...

suyula 5y ago

They're bouncing them off the retroreflectors on the moon though, right? So that doesn't necessarily translate to being able to send messages to anywhere on the hemisphere.

7kay 5y ago
No, the radio waves bounce off the moon's surface. The retroreflectors are not necessary for that, otherwise stuff like Earth-Venus-Earth bounces[1] would not be possible. [1]: https://amsat-dl.org/en/earth-venus-earth-experiment-of-amsat-dl-successful/ https://amsat-dl.org/en/earth-venus-earth-experiment-of-amsa...

7kay 5y ago

As others have already pointed out this exercise used a huge dish(a radio telescope[1]) and significant power. This is in no way an economically viable mode of communication. Using satellites in low earth orbit requires less power and a significantly smaller antenna. Putting LoRa on satellites has been done before, see e.g. [2]. [1]: https://en.wikipedia.org/wiki/Dwingeloo_Radio_Observatory https://en.wikipedia.org/wiki/Dwingeloo_Radio_Observatory [2]: https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=4657&context=smallsat https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=4...

karteum 5y ago

Well, here in that case they were using an approach that would be illegal by EU regulations (not sure about US) considering the EIRP limits :) And if you want real low-power long-range communications with the other side of the earth, you may be interested to have a look at WSPR https://en.wikipedia.org/wiki/WSPR_(amateur_radio_software) https://en.wikipedia.org/wiki/WSPR_(amateur_radio_software) !