Blagojce "Bill" Kolicoski Hits a 25-Mile Range with a 3D-Printed Yagi-Style LoRa Antenna

Software developer Blagojce "Bill" Kolicoski has demonstrated how to get a dramatic range boost from off-the-shelf LoRa transceivers — using a custom-designed 3D-printed directional antenna tuned specifically for 868MHz.

"[Previously,] I tested a [LoRa] module with omnidirectional antenna that reached up to 20 kilometers [around 12.4 miles]," Kolicoski explains, "but I wanted to push the limits even further. So, I decided to build a directional antenna and test it from a location 40 kilometers [around 24.9 miles] away — in a different country!"

LoRa transceivers have recently become a hot topic thanks to an explosion in popularity of the Meshtastic project, a community-driven effort to provide mesh networking for data and text over LoRa links between low-cost nodes. LoRa is designed for long-range operation at low power levels, which is reflected in its relatively low data rates — but it's possible to boost the range even further by ditching the stock antenna provided with most transceivers in favor of something better.

"I'm completely new to designing antennas so to make my life easier I've used an online calculator to 'design' the antenna," Kolicoski admits. "I entered 10mm for the boom diameter and I selected it to be square for easier [3D] printing later, I entered 2mm for the elements diameter because that was the diameter of the wire that I had on hand and I also tell it to work on 868MHz and to have 5 elements."

The resulting Yagi-style antenna design was then translated to a 3D-printed boom that spaces the wire elements out as specified by the calculator — each of which is also a specific length, tuning the antenna to a specific frequency. The reason for choosing a Yagi style design over something like a dipole antenna: directionality, boosting range by rejecting signals that aren't coming from the front of the antenna.

"I used a website called 'HeyWhatsThat' to figure out what is the furthest point that I can see from my balcony that is also easy to get to," Kolicoski writes of the testing process. "Looking around, I found a place in neighboring Greece that was about 40km away that I can get to by car so I went there. On location, I pointed the antenna in the direction where my base station was placed and immediately I was able to get a response back. The antenna worked without any issues and without any dropped pingbacks."

The project is written up in full on Instructables, where you can also download the antenna design; the 3D print file for the boom is available on Maker World under a Creative Commons Attribution-ShareAlike license.