Internet of Things: Mapping The Things Network LoRa Coverage with TTN Mapper

Out of curiosity I have been trying to establish the range in which my LoRa gateway can receive packets, first off I started using the tools by Radio Mobile Online which allows you to determine coverage estimates based on the antenna positioning details and the height profile of the area around your antenna, you can give it a go yourself over at http://www.cplus.org/rmw/rmonline.html.

I was quite suprised to see the range of a kilometre or so from my house considering I live in a small dip in the landscape and thought the estimate was unlikely. Therefore I wanted to try and validate the coverage for myself, however I have no GPS module for Arduino so I either had to buy a GPS sensor and get this to periodically send the location over LoRa and then go for a walk with this device powered on or have a complex arrangement of tracking my position on my smart phone and then trying to match my position to the time stamps of the packets received by the gateway, this obviously would take some time to get setup, so I searched to see if anyone else had tried mapping LoRa networks when I discovered ttnmapper.org, a community effort to map The Things Network coverage.

To use TTN Mapper you have to have a LoRa node which periodically sends a packet to The Things Network via a gateway, you then walk with this device powered up and your smart phone running the TTN Mapper app, the app listens for packets from your node via MQTT and when it receives a packet submits the receive signal strength, receiving gateway and GPS location to the TTN Mapper API which publishes the coverage data onto the TTN Mapper website for everyone to view. Looking at the Netherlands and Switzerland on these maps shows how popular LoRa is in these countries and some cities have very good coverage indeed.

Here is the coverage map for Zurich for example…

All in all pretty good mapping for a community driven LoRa “war driving” effort so to speak.

Anyway, what about the coverage for my own gateway? Well I realised I need to somehow power up the LoRa node on the move and due to the laws surrounding duty cycle I will have to rate limit my mapping so it may take some time and walking slowly around the local area to get decent resolution. I am off to charge up the largest USB power bank I own and tommorow I will hit the road in a breif stroll around the neighbourhood to test out how TTN Mapper performs and to get an idea of what my coverage looks like. I will then compare the results to the mapping from Radio Mobile Online to see if there are any similarities. Keep an eye out on my blog over the next few days for the results.

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