I need to map the locations of research plots in remote forested areas with no cell signal. I use the RS2+ as the base station and an RS4 rover and communicate via LoRa. In clearings, I can only get 200-300 meters away from the RS2+ before the signal drops. And, the signal cuts out after only 3-4 meters once I enter the trees. Everything I read beforehand indicated I ought to be able to communicate for up to 2 km.
I use a frequency of 915.0 MHz, output power = 20 dBm, air data rate = 9.11 kb/s. On the RS4, I have the update rate set to 5 Hz.
welcome to the forum Nathan
If you search here you may find multiple complaints about the LoRa radio link being the Achilles tendon of the Emlid receivers (my opinion).
It’s a bit disappointing that complaints are still coming in even though you have the RS4 receiver.
To remedy this (and I believe I have tried every possible permutation & combination of LoRa adjustments) I finally acquired the 2 Watt LoRa amplifier from Topotrade (Not available in the Continental USA). A real game-changer. Otherwise, you could try a 35 Watt UHF radio but this will significantly add to the bulk of your kit plus a $2000+ purchase price. It will also require licensure in some jurisdictions.
Yes that would give you the 1watt instead of a 0.1 watt. I have yet to hit drop out range with the rs4 and my aftermarket antenna 1000’ to 2000’ in the woods no problem as long as no hills in the way.
No apologies needed. I can understand practical reasons why you might have wanted to do this.
Bear in mind given your initial experiences in that forest that 2km is still unlikely
Radio propagation isn’t linear; it’s inverse square and power diminishes more rapidly with distance. E.g. with all else being equal (and it typically isn’t) to get double distance would require 4 times the power, to get 4 times the distance would require 16 times the power etc.
That said if your RS4 base doesn’t give you what you want there are configs such as those mentioned above and also techniques that can extend your working reach.
There is definitely no need to apologize. It is always great to ask questions and exchange ideas with other users. That’s exactly what the forum is for.
Regarding range, LoRa is a low-power radio, so it generally requires a clear line of sight without obstructions between the base and rover to achieve optimal performance. Still, 200-300 meters in open clearings is definitely unusually short, and we’re keen on helping you improve this.
Testing with two RS4 units is a great move. The RS4’s higher LoRa transmission power and all-band tracking on both ends should make a noticeable difference. I look forward to hearing how that test goes.
In the meantime, here are a couple of practical tweaks you can try to optimize the link:
You can test a different LoRa frequency, as local interference can heavily degrade a specific channel. Try switching to another available frequency in Emlid Flow on both units.
Raising both the base and rover as high as possible can help with line of sight.
The 2 km figure is usually a best-case line-of-sight number, so expecting it under a wet canopy is optimistic. Foliage and moisture both absorb 900 MHz energy, and a hill or dense trunk line will cut it further. Going to 1 W helps, but antenna height and placement often matter more than raw power. Before buying another unit, try raising the antenna and testing at a few fixed distances to see where packets actually start dropping.
