4 ms·

Recently some people experimented with LoRa in mines. Seems like the extreme sensitivity (down to -146dBm) is able to deal with the reflections there pretty we

Recently some people experimented with LoRa in mines. Seems like the extreme sensitivity (down to -146dBm) is able to deal with the reflections there pretty well down there. But: that's not Through-the-Earth. It's Within-The-Earth. (I have no details regarding the used band, antenna nor exact setup)

xanderlewis 2y ago
There seems to be so much excitement around LoRa, but I don’t really get it… What is the use/appeal?
- rcxdude 2y ago
  it's low power and long range, but low bandwidth. For a lot of applications, that's pretty useful.
- ElectRabbit 2y ago
  It's extremely sensitive to weak signals (-146dBm.. for comparision Wifi becomes unreliable below -80dBm and unuseable at -90dBm) and thanks to its chirp character very robust in presence of noise (jammers, alien stations, etc.). You either can parametrize it for speed or for robustness - there are a lot of parameters to fine tune it. Also it's easy to switch even faster modes (that are not LoRa) by just sending a few SPI commands. The documentation of the chips is stellar. There are good software libs around, also Zephyr supports a few of them. Also Semtech is extremely hobbyist friendly. If you want to play around with them: use LoRaWAN and The Things Networks. There are a lot of basestations around - at least in Europe. Getting >30km links with a still a metric ton of SNR left pretty much the standard. Even with lightly obstructed LoS. I've seen experiments with balloons that hat >400km links with plenty to SNR left. Practically: we are using a single LoRaWAN basestation to gather telemetry from a giant industry complex. No problem even if the sensors are placed deep in the basement.
  - xanderlewis 2y ago
    Cool!
slow_typist 2y ago
Not claiming to understand lora but I guess that is probably because it kinda sweeps through the band so reflections which belong together come on the same frequency and therefore can add to the reconstruction of the signal (waves hands)

xanderlewis 2y ago

There seems to be so much excitement around LoRa, but I don’t really get it… What is the use/appeal?

rcxdude 2y ago
it's low power and long range, but low bandwidth. For a lot of applications, that's pretty useful.
ElectRabbit 2y ago
It's extremely sensitive to weak signals (-146dBm.. for comparision Wifi becomes unreliable below -80dBm and unuseable at -90dBm) and thanks to its chirp character very robust in presence of noise (jammers, alien stations, etc.). You either can parametrize it for speed or for robustness - there are a lot of parameters to fine tune it. Also it's easy to switch even faster modes (that are not LoRa) by just sending a few SPI commands. The documentation of the chips is stellar. There are good software libs around, also Zephyr supports a few of them. Also Semtech is extremely hobbyist friendly. If you want to play around with them: use LoRaWAN and The Things Networks. There are a lot of basestations around - at least in Europe. Getting >30km links with a still a metric ton of SNR left pretty much the standard. Even with lightly obstructed LoS. I've seen experiments with balloons that hat >400km links with plenty to SNR left. Practically: we are using a single LoRaWAN basestation to gather telemetry from a giant industry complex. No problem even if the sensors are placed deep in the basement.
- xanderlewis 2y ago
  Cool!

slow_typist 2y ago

Not claiming to understand lora but I guess that is probably because it kinda sweeps through the band so reflections which belong together come on the same frequency and therefore can add to the reconstruction of the signal (waves hands)