I'm interested in in low power radio tech and been running LoRa (Lo
nge) gateways for the past 6 months using a combination of Raspberry Pi + a LoRa gateway board from the either iMST or RisingHF.
It's fun to run license-free (ISM: 868 or 915Mhz bands) battery powered sensor nodes reaching distances up to 5Km in the city and there is already a great community and lots of open source at http://www.thingsnetwork.org
LoRa tech is unfortunately proprietary and worse, all hardware comes from a single company: Semtech. This is especially bad for gateways because you can't just buy the chips - SX1301, a type of FPGA to listen on 8 RF channels with different encodings. Only licensed gateway manufacturers can get the chips, all hardware has to approved in France and even the data sheets are under secretive NDAs.
This meant that true multi-channel LoRa gateway boards have been priced well upwards of $100
However China delivered and about 2-3 months ago these gateway chips began appearing in Taobao - costing not more than $2!
I ordered 10 chips from https://world.taobao.com/item/524964459840.htm#detail
and they arrived in a plastic bag. No problem, no question asked.
There is already a project at https://hackaday.io/project/13373-lora-concentrator
using this chip but it has design bugs, doesn't work and worse had no more progress. The lack of public information is jarring to anyone hoping to participate, if you even publish the datasheet anywhere public Semtech will send a takedown notice in a few hours.
Hopefully this isn't the case here
and I hope to continue the project and document it as I go along.
To get things started here's the datasheet for the SX1301 chip:https://www.scribd.com/document/333101561/SX1301-Copy?secret_password=v2igCgDr6qb0vmXMVT0D