LoRa gear can be great for doing radio communications in a light-weight and low-power way. However, it can also work over great distances if you have the right hardware—and the right antennas in particular. [taste_the_code] has been experimenting in this regard, and whipped up a simple yagi antenna that can work at distances of up to 40 kilometers.
The basic mathematics behind the yagi antenna are well understood. To that end, [taste_the_code] used a simple online calculator to determine the correct dimensions to build a yagi out of 2 mm diameter wire that was tuned for the relevant frequency of 868 MHz. The build uses a 3D-printed boom a handle and holes for inserting each individual wire element in the right spot—with little measuring required once the wires are cut, since the print is dimensionally accurate. It was then just a matter of wiring it up to the right connector to suit the gear.
The antenna was tested with a Reyas RYLR998 module acting as a base station, with the DIY yagi hooked up to a RYLR993 module in the field. In testing, [taste_the_code] was able to communicate reliably from 40 kilometers away.
We’ve featured some other unique LoRa antenna builds before, too. Video after the break.
Further – Unless my Dad is extending the signal range!
Farther applies to physical distance, further applies to more figurative uses. It’s being used correctly
https://www.youtube.com/watch?v=exCYSfQod14
Good start. Now add a balun, then stick it on a VNA and learn the joy of a gamma match. Then fine tune the element lengths.
Betcha there’s at least 3 dB sitting on the table.
Really difficult to get a gammaatch right at those frequencies because the dimensions are tiny and critical. Far easier to match it with a coax transformer
Before using one it is worth checking if local regulation don’t limit the ERP which is common on ISM bands. Even with limited output power a directional antenna can improve connectivity by improving SNR at the receiving end.
My Lora installations were reaching nodes three or four hundred kilometres away with off the shelf antennas.
And…
I’m pretty sure this was substantially cheaper.
And? No and. Just that 40 km is not very far at all. I’ve had farther than that with the bent wire on a Semtech module.
slow news day when a yagi antenna is headlined.
LoRa? Does that mean this is meshtastic capable? Thanks
actually was going to watch video but it is 32 min long and contains paid promotional material. So I’ll be annoying and ask- did he compare that antenna to… not that antenna? I was under impression LORA was optimized for low power, long range (LoRa…. right in the name) so 40km may not be that impressive.
In any case that little antenna is pretty adorable actually.
73
Hmmm.. There is really nothing special about antenna gain, modulation coding and distance. The two primary limits for limitation of coverage distance are terrain blockage (earth curvature, dirt or buildings in the way of the signal, atmospheric refractivity index) and localized interference generated by other transmitters or noise sources.
Inmarsat has no problem at all communicating 23,500 miles from earth to space and (additionally 23,500 miles) back with 400 milliwatts and a low gain, nearly omni directional satphone antenna. (at 2 GHz)
Yes antenna gain improves the signal strength. Antenna directionality improves the discrimination of localized and distant received interference. Reduced bandwidth and forward error correction (LoRa) improves transmitted power spectral density and reduces the received signal strength requirements and carrier to noise and interference thresholds.
The claim that any magic antenna gets you a radio path of XX miles is more about anecdotal terrain and obstruction loss between the endpoints and how quiet the interference is at the 2 locations.
Signal strength is predictable. It takes 6 dB to double the distance, given equal modicods and C/(N+I). (20 log(10) distance)
Nice article about building a Yagi antenna.
The premise that it will give you X miles of coverage distance, though,….
There’s no reason that this Yagi antenna on LoRa couldn’t communicate 150 miles between 2 radio quiet 5,000 ft mountain tops.