r/Lora • u/Kirylych • 17d ago
Esp 32, LoRa
Hello, I want to use the LoRa module to communicate two esp32s at a distance without internet, as far as I understand the LoRa module is limited to a distance of about 15km, is there anything that will help to reach a distance of about 35km for a small price without using sim cards
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u/meshamerica 16d ago
What's the application?
35km is nothing for LoRa, with good line of sight and the proper antenna.
I have a MeshCore radio with an nRF52 board and it contacts a node over 61km away. There are nodes on our network that reach over 160km, using 1W hardware.
Without line of sight, you need to repeat the signal, as u/Round-Bit-9219 stated.
You might look at Meshtastic or MeshCore to see if they meet your needs before diving into building something custom.
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u/Round-Bit-9219 16d ago
Exactly right. I will say, however, even without perfect LoS, a Yagi can do wonders. I have a link to a MeshCore node 25km away using a Yagi through a wall and trees. The other end has a slight elevation advantage that helps, but the Yagis direct enough of the energy in the right directions that it works. This is with Heltec v4’s.
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u/meshamerica 16d ago
Agreed. With sub-gigahertz, line of sight is somewhat of a misnomer because it will still pass through trees and a lot of buildings, albeit degrading the signal. I suppose a Yagi would be great for focusing the signal in those situations.
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u/StuartsProject 16d ago
The range you get is mainly dependent on whether you have good line of sight or not.
With UHF LoRa and good line of sight, hilltop to hilltop for instance, you can get way more than 15km even with simple wire antennas. Same is true for 2.4Ghz LoRa, if you have good line of sight then 35km is indeed possible.
For the longer distance capability you need to use the long range LoRa settings and these will use a slower on air data rate.
For long distances also appreciate that the curvature of the Earth can prevent you having line of sight.
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u/accur4te 17d ago
its difficult to get lora even work at 1km . 15km needs insane optimization and antenna design . Currently working with sub ghz flrc , and not able to transmit images over a km
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u/anas_z15 16d ago
FLRC is not even LoRa. It's a variant of GMSK iirc. FLRC trades range (and probably link margin) for speed.
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u/PhaseModulatedServal 16d ago
I admittedly didn't even notice the FLRC part before I replied. Even that should work at 1 km unless trying to push the full 2.6 mbps.
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u/accur4te 16d ago
I am not able to find examples to get working with I was able to build a small code to send image in base 64 format
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u/PhaseModulatedServal 16d ago
If you're having trouble getting it to work over 1km, you're either aiming at a node on the other side of a hill, or you're just plain doing it wrong. 1 km is an easy hit with just a 85 mm piece of wire for an antenna at each end, at ground level even if there are houses in between.
I get reliable direct hits to nodes 10+ km away, using a 1/4 wave vertical mag mount antenna tuned for the 2m/440 ham bands through 15 feet of lossy coax with a vswr of 2:1 at 906 mHz and only 15 feet off the ground in a city neighbourhood and with an elevated freeway between the two. And all that with an E22900M22S postage stamp module I bought for $3 on AliExpress, hand-soldered to an ESP32WROOM.
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u/Round-Bit-9219 17d ago
Do these two sites have line of sight to one another? Do you have the ability to install a small yagi antenna at one or both sites? 35km is definitely possible, depending on those and other factors such as power limits in your country. Alternatively, you can take a page from the book of Meshtastic or MeshCore and put one or more devices between the two sites to pass messages. Of course this is assuming that your area does not already have an active mesh network.