How farm sensors send data for miles

Battery powered soil sensors wake up, measure moisture and temperature, and send a short burst of data using a long-range, low-power radio method such as LoRa. A gateway on a tall mast hears packets from sensors across the farm and forwards them to the internet. The signal weakens with distance, and the free space path loss formula tells you how much before crops and hills take their share.

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Add crop canopy and terrain losses (40 dB)

Step through it

Sensors in the fieldEach probe measures the soil and sleeps most of the time. A packet of a few dozen bytes every 15 minutes lets a battery last for years.
Spread spectrum chirpsThe radio sweeps its frequency up in chirps. Slow chirps can be decoded even when the signal is far below the noise, which buys range at the cost of data rate.
The gatewayA gateway high on a mast listens on several channels at once and forwards every packet it hears to a network server over cellular or Ethernet.
Distance costs decibelsEvery doubling of distance adds 6 dB of path loss. In open air, 30 km at 915 MHz still works on paper.
Real fields are not free spaceCrops, trees and rolling ground soak up much more signal. Add 40 dB of losses and the far sensor drops out, so the gateway moves closer or higher.

Free space path loss

FSPL in decibels = 20 log10(distance in km) + 20 log10(frequency in MHz) + 32.44, the standard free space formula from radio engineering. It describes how a radio wave spreads out over a growing sphere, so it rises 6 dB every time the distance doubles and is a bit lower at lower frequencies.

This model assumes a 14 dBm transmitter, 3 dB of combined antenna gain and a best case receiver sensitivity around minus 137 dBm at the slowest data rate. The 40 dB terrain loss is a rough stand-in; real losses depend on antenna height, crop height and ground shape.

Try it: with terrain losses on, slide the distance up until the link reads out of range, just past 13 km at 915 MHz. Switch to 433 MHz and the same distance works again because the path loss is about 6.5 dB lower.

Planning a farm network

Gateway height matters as much as distance, because the signal needs a clear zone above crops and terrain. It pays to test coverage across the field with a portable sensor before installing permanent probes.

Where Avid uses this

Field sensor networks like this feed the soil moisture data that precision irrigation tools such as Avid's VerdantaIQ use, an approach documented with a 58 percent water reduction at IBM TechXchange 2026.

Sources

Basics of LoRa Technology for Crop and Livestock Management (AE1999)NDSU Extension
Multi-Boundary Empirical Path Loss Model for 433 MHz WSN in Agriculture Areas Using Fuzzy Linear RegressionSensors (via PubMed Central, NIH)
LoRa-Based IoT Network Assessment in Rural and Urban ScenariosSensors, MDPI (open access)

How to cite this model

Avid Solutions International. (2026, November 11). How farm sensors send data for miles [Interactive 3D model]. Avid Field Lab. https://avidsolutionsintl.com/explore/lora-sensor-network

Last updated November 11, 2026

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