A few weeks ago I decided I’d like to compare the results of Radio Mobile Online and my actual LoRa coverage using TTNMapper, and although I have not walked all roads within the coverage prediction I have walked the roads around my house and the results are quite underwhelming so far. Here is a very primitive overlay of my TTNMapper results vs the shading from Radio Mobile Online.
You can quite clearly see the difference between the Radio Mobile Online and TTNMapper map types and the area where the coverage stops in real life is far inferior compared to the Radio Mobile Online prediction, there are a number of reasons for this…
a) Radio Mobile Online only takes into account terrain not buildings, and unfortunately my house is walled in by other housing and apartment buildings.
b) Radio Mobile Online probably assumes that you are using a proper antenna on a proper mount outside of the building, unfortunately my LoRa gateway is a bad home made antenna inside of a window on the ground floor.
c) I am unsure of the resolution of the terrain data in Radio Mobile Online, it is safe to say I live in a small dip in the landscape that is very slight, but significant enough to affect coverage in my opinion, if the resolution of Radio Mobile Online terrain data is not fairly high it’ll probably miss the fact my house is lower than the surrounding terrain.
d) My tests were only using SF7 as I only have an el cheapo single channel, single spread factor receive only gateway.
All in all quite disappointing compared to the results from others who have had antennas on top of hills with clear line of sight over many miles, but not really a bad thing as all of my LoRa devices are in my house anyway. Hopefully after I move soon we should see some much nicer results (my new house is on top of a hill). However for sure unless you have perfect conditions I would not take the Radio Mobile Online predictions too seriously when working out your LoRa coverage.