Ground station for LoRa satellites
The arrival of small satellites that used LoRa for telemetry data has meant that less technically qualified persons, with a very low budget, can receive their signals.Thanks to TinyGS, there is now an open network of distributed ground stations, and more stations can be built to increase their coverage.The project presented here is a reasonably robust, dust-resistant and waterproof implementation of TinyGS ground station, using commercial off-the-shelf components. Ideal for outdoor usage
Key component: Heltec WiFi LoRa kit 32 v2 433mhz
The idea of using LoRa for satellite communications became obvious to many people for the following reasons:
- Uses unlicensed ISM band
- Availability of ready to use, low cost, easy to find electronic modules.
- Very long range, and low power communications
- Reception possible with very low level signals -120dBm
The last point is very important, since many commercial antennas can be used (homemade too!), even if they aren’t very efficient, are enough to receive signals. This was the Achiles’ heel of satellite communications until now
What is the project about?
This project is about a gateway between the Internet (WiFi) and LoRa @433Mhz using as much as possible of commercial off-the-shelf components, so not much expertise needed for assembly. The final key consists in downloading TinyGS firmware which allows something like:
- Download automatic firmware updates (OTA)
- The receiver will tune automagically to the nearest satellite in the sky
- Configuration of parameters using the local web interface
Bill of materials
COMPONENT DATASHEET - BUY LINK
- Heltec Lora Kit 32 V2 433MHZ ESP32 - buy it
- RP-SMA flange to U.FL pigtail - buy it
- 433 Mhz antenna SMA - buy it
- Generic 100x68x50mm waterproof enclosure box “Sonoff” - buy it
- M2.5 countersunk screw phillips - buy it
- M2.5 nylon lock nut - buy it
- M2.6 self-tapping B-type screw - buy it
- Screw terminal kf350 3.5mm 3 pin - buy it
- Female header 2.54mm - buy it
- 30 AWG wire wrap UL1423 PVDF - buy it
- PoE injector 48V 0.5A - buy it
- PoE Splitter D1398 module 5V 2A output - buy it
- SMA Female To RP SMA Male adapter - buy it
- Silicone Sealant Neutral RTV - buy it
- Waterproof silicone self fusing vulcanizing tape - buy it
PRINTED CIRCUIT BOARD SOURCE FILES REPOSITORY - BUY LINK
SOFTWARE - REPOSITORY
- TingyGS Firmware - download it
OPTIONAL COMPONENTS DATASHEET - BUY LINK
This article is not intended to be a step-by-step assembly guide, it will attempt to explain briefly what to do next. Depending on the components obtained, some instructions and their sequence may change slightly
Antenna connector drillings:
- Make 4 drillings with a bit slightly wider than 2.5 mm, that’s where the fixing screws will go.
- Make another drilling in the middle with a bit slightly wider than 4 mm, that’s where the pigtail wire will go. The drill assistant template can be found here.
Connectors and wire soldering
There are two options to power the station: using a simple 5V power supply or using a PoE adapter. The 5V power option requires less hardware, but is limited to a few meters of cable, however the PoE version requires a PoE injector, a PoE splitter inside the case, but it can be placed up to 100 meters away
- Solder LoRa module headers. This is not 100% necessary, because the module could be soldered directly to the board, however, using headers make it possible to disconnect the module at any time.
- Solder PoE splitter module header (if used!)
- Solder PCB screw terminals for ease of connection/disconnection of the power cable.
- Solder the power wires under the board, using PVDF coated wire when...