LoRa Distance Record

[Blaise]

OK, here's one for the folks that actually understand how EM propagation works in practice:

A couple of years ago, the current distance record was set for LoRa at more than 800 miles.  The communication was between a fishing boat and one of the buoys in its fishery across open ocean.  https://www.thethingsnetwork.org/article/new-lora-world-record-1336-km-830-mi

Frankly, I'm confused as to how that happened when, by my best guestimates, the unit on the buoy has a horizon at around 4 miles.  The one on the boat, due to its greater height, had a horizon at more like 15 miles, but that still doesn't make it better!

Now, I was under the impression that signals in the 800-1000 MHz range sere strictly line of site, with neither ground nor sky propagation.  Nonetheless, this event would imply that either I'm completely wrong about how EM propagation works, or somebody's fibbing...

[SteveShannon]

7 minutes ago, Blaise said:

OK, here's one for the folks that actually understand how EM propagation works in practice:

A couple of years ago, the current distance record was set for LoRa at more than 800 miles.  The communication was between a fishing boat and one of the buoys in its fishery across open ocean.  https://www.thethingsnetwork.org/article/new-lora-world-record-1336-km-830-mi

Frankly, I'm confused as to how that happened when, by my best guestimates, the unit on the buoy has a horizon at around 4 miles.  The one on the boat, due to its greater height, had a horizon at more like 15 miles, but that still doesn't make it better!

 

Now, I was under the impression that signals in the 800-1000 MHz range sere strictly line of site, with neither ground nor propagation.  Nonetheless, this event would imply that either I'm completely wrong about how EM propagation works, or somebody's fibbing...

UHF is line of sight until it is reflected or refracted by some atmospheric condition.  Google Tropospheric Ducting.

Physical features such as mountains can also cause reflection or refraction.

[WRYZ926]

Our GMRS repeater is at least 100 miles away from any other repeater that uses the same channel and tones. I am 80 miles away from the other repeater. Normally there is not any issues. But when tropospheric ducting happens, one of the other repeaters can be heard at full strength and will also key up our repeater. 

I have another GMRS repeater that is 50 miles west of me. On occasion I talk to a guy that lives 150 miles east of me on that repeater that is 50 miles west of me. It's amazing how far you can reach when atmospheric conditions are just right.

This goes for any band/frequency from HF all the way up to 900 MHz and higher.