Level · Comparison

Radar vs Ultrasonic

Side by side comparison: how they work, where each fits, and which to choose.

Quick answer: Radar works in almost any tank, including vapour, pressure and high temperature; ultrasonic is cheaper and fine for water, sumps and open channels.

Radar vs Ultrasonic: Comparison Table

Aspect	Radar	Ultrasonic
Signal	Microwaves	Sound pulses
Affected by vapour, temperature, pressure	Hardly	Yes, speed of sound changes
Foam	Can weaken echo	Often absorbs signal
Pressure rating	High	Usually near atmospheric
Blocking distance	Small	Larger
Cost	Higher, falling	Lower

Choose Radar when

Process tanks with vapour, pressure or heat
Long ranges, solids silos (80 GHz)

Choose Ultrasonic when

Water tanks, wet wells, open channel flow
Low budget, simple service

Key Differences Explained

Both are top mounted, non contact time of flight devices. Ultrasonic relies on the speed of sound in air, which depends on temperature and gas composition; radar uses microwaves, which are almost unaffected.

Modern 80 GHz radars have narrow beams and short blocking distances, closing the price gap.

Related Glossary Terms

GlossaryRadar Level TransmitterA radar level transmitter measures level from the travel time of microwaves reflected from the…GlossaryUltrasonic Level TransmitterAn ultrasonic level transmitter measures level from the time sound pulses take to travel to the…GlossaryBlocking DistanceBlocking distance is the zone just below an ultrasonic or radar sensor where it cannot measure,…GlossaryDielectric ConstantDielectric constant is the relative permittivity of a material; it sets how strongly a liquid…GlossaryFalse Echo SuppressionFalse echo suppression teaches a radar or ultrasonic transmitter to ignore echoes from fixed…

Free Calculators

CalculatorRadar Level CalculatorFree online calculator with formula and worked example.CalculatorUltrasonic Level CalculatorFree online calculator with formula and worked example.

Free Downloads

Free downloadRadar Level Transmitter Commissioning ProcedureFree step by step procedure, Word and PDF.

Frequently Asked Questions

What is the difference between Radar and Ultrasonic?

Radar works in almost any tank, including vapour, pressure and high temperature; ultrasonic is cheaper and fine for water, sumps and open channels.

Can ultrasonic be used in a closed chemical tank?

Often not well; vapours change the speed of sound and condensation affects the sensor.

Does radar work on low dielectric liquids?

Yes, but echoes are weaker; check the dielectric constant against maker limits.

Which is better for open channel flow?

Ultrasonic is common and cheap; radar is used where wind, sun or foam cause problems.

Learn more on the blog

Ultrasonic level transmitter working

A practical guide on instrumentationblog.in that goes deeper into this topic with field examples.

Read Full Article

More Comparisons

LevelDP Level vs Radar LevelDP level is proven, works in closed and pressurised vessels and can measure density or interface,…LevelDisplacer vs Guided Wave RadarDisplacers are proven for level and interface but density dependent with moving parts; GWR has no…LevelFloat Switch vs Vibrating ForkFloat switches are simple and need no power but can stick; vibrating forks have no moving parts,…PressureCapacitive vs PiezoresistiveCapacitive sensors excel at low ranges, DP and stability; piezoresistive sensors are compact, robust…PressureRemote Seals vs Impulse LinesRemote seals avoid plugging, freezing and leaks but add temperature error and slower response;…Control ValveGlobe Valve vs Ball ValveGlobe valves give precise throttling and the best cavitation and noise options; segmented ball…

All comparisons · Instrumentation glossary