TDR (Time Domain Reflectometry)

Guided radar is based on the TDR principle, which is a well known technique in the continuity measurement of communication cables.

Pulses of low power microwaves (nano-seconds), are sent along the conductors rods or cables.

At the point where the waves meet the product surface, the waves are reflected by the product. The intensity of the reflection depends on the dielectric constant of the product.

The higher the dielectric constant, the stronger the reflection will be, e. g. up to a 80% reflection for water.

The instrument measures the time between emission and reception which is proportional to the distance.
Dust, vapour, foam etc. will not affect the level measurement as long as they have a low dielectric constant. Neither temperature, pressure and dielectric constant variations, nor tank form will influence the precision of the measurement.