I often get asked what range you can get in ‘typical conditions’ using LoRa. There is a simple answer;

“There is no such thing as typical conditions.”

On several occasions constructors have got in touch and said; “I am only getting 1KM, yet you are quoting hundreds of KM, what is wrong with my set-up?” The answer to that is also simple;

“There is probably nothing wrong”.

It is not commonly understood how much the range\distance of communications at UHF can vary. Of course most people expect a difference between an urban area and hilltop to hilltop, but the actual differences are often a surprise. Are the communications over flat or hilly terrain, in urban, rural or forest or perhaps ground to satellite or ground to high altitude balloon?

I was fortunate during the radio testing for the $50SAT project to be able to develop a real world rule of thumb. Whilst testing the Morse beacon (on 437Mhz) I wondered if cutting the transmit power between dits and dahs would make an audible difference, there was an advantage in doing so as it saved around 33% of the battery power.

So I set-up the $50SAT transmitter board running the Morse beacon in my garden and wandered away up the road with my Yaesu FT60 hand-held till the Morse beacon was only just audible above the background noise. This was at a distance of 1km. I live in an urban area and its relatively flat.

The very same $50SAT transmitter board was put into orbit in November 2013. Some months later I was walking into town (it was a nice day) and $50SAT passed at approx 1200km distance. I heard the Morse Beacon very clearly with my Yaesu FT60.

In an urban environment the limit of reception was 1km, yet with the exact same transmitter and receiver and clear line of sight, the reception distance was 1200km, probably more.

That is where my 1000:1 rule comes from.

Thus whilst you might get 400KM with LoRa from the ground to a high altitude balloon, do not be surprised if at ground level in a city you get 400M or less.

This difference is also why it is so difficult to compare reception at different locations. I might get 1KM in my locality, the same equipment might cover anywhere between 250M and 10KM+ elsewhere. The differences are a good reason to be clear about the conditions applying to a reception report, preferably with pictures of the area.

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