Emlid Reach RS3 LoRa vs UHF Range Comparison | Farmland Roads

The purpose of this exercise was to compare the real-world performance and correction range of the internal 902 MHz LoRa radio on the Emlid Reach RS3 against a 450 MHz Harxon UHF setup using Trimtalk™ protocols. The tests were conducted down relatively flat, unobstructed farmland roads to isolate radio frequencies under various conditions.

For the evaluation, an Emlid Reach RS2+ functioned as the Base setup, transmitting to the Emlid Reach RS3 rover. The rover receiver was securely mounted to the roof of a car traveling at a consistent speed of 25 mph. Throughout the drive, the real-time age of corrections was actively monitored inside MicroSurvey FieldGenius for Android until the signal was dropped entirely. Once the receiver flipped to autonomous operation, the vehicle backtracked until corrections reacquired to securely register a fixed shot.

Day 1 Test

Conditions: 34° F, 2 MPH SE Wind, 81% Humidity

During the first day of monitoring, the baseline power output of the External Long Range Radio Kit was dialed down to its absolute minimum setting of 5 W, matching up against the LoRa radio operating at its standard 0.1 W. (Note that the external UHF radio capability can be boosted all the way up to 35 W if required).

Even though the chosen position for the Base station on Day 1 suffered from a less-than-ideal elevation profile, the raw performance gap was clear. The team achieved an additional 21% more baseline distance utilizing the UHF 450 MHz band relative to the integrated 902 MHz LoRa setup.

Day 2 Test

Conditions: 45° F, 4 MPH S Wind, 94% Humidity (Thick fog and heavy rain)

For the second run, the external UHF radio remained on its lowest 5 W output vs the LoRa radio at 0.1 W. To evaluate top-end environmental constraints, the Base location was adjusted to a notably higher elevation point to maximize line of sight.

However, atmospheric conditions changed aggressively, bringing heavy rain and thick fog to the farmland roads. These adverse weather blocks significantly impacted the baseline distances for both frequencies:

• The 450 MHz UHF correction stream experienced a 44% range reduction.
• The 902 MHz LoRa correction stream experienced a steeper 65% range reduction.

Ultimately, even with heavy precipitation mitigating performance across the board, the UHF radio frequency proved substantially more resilient—maintaining a usable range that was more than double that of the internal LoRa signal.

Conclusion

Across both variations in terrain elevation and atmospheric disruptions, our External Long Range Radio Kit connected to the Emlid base delivered significantly increased range over standard 902 MHz LoRa. Utilizing MicroSurvey FieldGenius for Android to track precision limits, the UHF workflow demonstrated distinct reliability advantages for long-baseline surveying.