How far a LoRa tank sensor reaches, and what cuts it down

A LoRa tank sensor at 915 MHz reaches a mile or more when the tank and the receiver can see each other, and less when hills, brush or buildings stand between them. The 30 miles the chip maker claims are what the radio does with nothing in its way: what decides the reach of yours is the ground between the tank and the house.

By Luke Patterson, co-founder of Trivertix. Last checked October 26, 2026.

The figures you will see, and what each means

Range figures for LoRa run from a few miles to thirty, and they are all true of something. The chip maker's figure is for antennas with open air between them. A figure from a field is for that field. Ask of any figure what lay between the two ends.

Source, read October 26, 2026: Semtech: What is LoRa?.

Semtech, rural: Up to 30 miles
Semtech, in cities: Up to 3 miles
Trivertix, in the open: A mile or more with a clear line of sight
Trivertix, tested: Three-quarters of a mile through hills and mesquite on our pilot ranch

Semtech makes the LoRa chips, and gives its figures on its own page. The last line is from the first Trivertix units, on stock tanks on the Patterson ranch outside Karnes City, Texas.

Line of sight is more than seeing the tank

A radio signal does not travel down a thin line. It fills a space shaped like a football around the straight line between the two antennas, called the first Fresnel zone, widest halfway along. Radio planners hold that it should be 80 percent clear of obstacles, and must be at least 60 percent clear.

Source, read October 26, 2026: Wikipedia: Fresnel zone.

A link of 0.5 mile: 27 feet in radius, 16 feet of it to keep clear
A link of 0.75 mile: 33 feet in radius, 20 feet of it to keep clear
A link of 1 mile: 38 feet in radius, 23 feet of it to keep clear
A link of 2 miles: 53 feet in radius, 32 feet of it to keep clear

Those are the radius halfway along a link at 915 MHz, and the part of it to keep clear at the least. Over a mile the zone is 38 feet in radius at its middle, and an antenna on a tank and one at a window are a few feet off the ground. So over flat ground the earth itself takes a bite out of the zone, and a rise, a line of trees or a barn near the middle takes more. Less clearance does not end a link at once. It costs signal, and the signal to spare is what range is made of.

The curve of the earth is not the limit at a mile

Over a smooth earth, each antenna can see out to its own horizon, a distance that grows with the root of its height. Radio waves bend a little in the air, so the radio horizon lies a little past the one your eye sees.

Source, read October 26, 2026: Wikipedia: Line-of-sight propagation.

An antenna 8 feet up on a tank: Sees about 4.0 miles
A receiver 5 feet up at a window: Sees about 3.2 miles
The two together: About 7 miles of smooth ground

So on level ground the curve of the earth comes between a tank and a house only miles beyond the reach given above. What stops a tank sensor short is nearer: the rises between the two ends, and what grows and stands on them.

What cuts the reach down

A hill or a rise between the tank and the house, above all one near the middle of the link.
Thick brush and trees, which soak up signal along every yard they fill.
Metal in the way: a barn, a steel tank, a metal roof or a shipping container.
The house the receiver sits in: walls, a metal roof, and appliances between the receiver and the window.

Each of these takes some of the signal to spare. One may cost nothing you notice; two or three together can end a link that would carry for miles over open ground.

Getting the most from the link

Most of a link's reach is decided where the two ends sit. None of these takes a tool.

Put the receiver at a window

A window that faces the tank, as high in the house as you can, and away from metal. Moving the receiver costs nothing and is the first thing to try.

Lift either end

Height lifts the zone the signal fills off the ground and over the brush. A receiver upstairs hears farther than the same one on the ground floor, and a few feet can matter more than any other change.

Walk the line

Look along the straight line from the tank to the house. A rise near the middle hurts more than one near either end, since that is where the zone is widest.

Try it before you mount it

Pair the transmitter and set it where it will go, then see that the receiver shows its reading, before anything is fixed to the tank.

Where Trivertix fits, and where it does not

Trivertix sends each reading from the tank to a receiver in the house: LoRa at 915 MHz from transmitter to receiver. No SIM card, and no cellular or satellite modem. The receiver shows the level on its own display, and joins your Wi-Fi for the app. Its reach is a mile or more with a clear line of sight; with the pilot units the link held at three-quarters of a mile through hills and mesquite on our pilot ranch, in Karnes County, Texas.

It does not fit every tank. The radio has to reach a receiver in a building with power, so a tank on the far side of a big pasture, or behind more than one hill, is a job for a satellite or cellular monitor, which needs no building nearby and bills a plan for the connection. If your tank is more than a mile out, write to us at feedback@trivertix.com before you order.

Satellite, cellular or radio: five monitors side by side

Questions about LoRa range

How far can a LoRa water tank sensor transmit?

As far as the ground between the tank and the receiver lets it. Semtech, which makes the LoRa chips, claims up to 30 miles in rural areas and 3 miles in cities, which is what the radio can do with nothing in its way. Trivertix gives a mile or more with a clear line of sight, and the link held at three-quarters of a mile through hills and mesquite on our pilot ranch.

Does a LoRa radio need a clear line of sight?

Not a perfect one, but its reach falls fast without it. The signal fills a space around the straight line between the antennas, about 38 feet in radius halfway along a mile at 915 MHz, and radio planners hold that it must be at least 60 percent clear. A hill, a stand of brush or a metal barn in that space costs signal, and enough of them end the link.

Does mounting the antenna higher help a LoRa sensor reach farther?

Yes. Raising either end lifts the space the signal fills off the ground and over the brush. The curve of the earth is not what stops a link of a mile: two antennas 8 and 5 feet up can see each other over about 7 miles of smooth ground. The rises and what grows on them are what stop it.

What blocks a 915 MHz radio signal?

Ground first: a hill or a rise between the two ends. Then thick brush and trees, metal buildings, steel tanks and metal roofs, and the walls of the house the receiver sits in. A receiver set low behind an appliance hears less than the same one at a window that faces the tank.

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