Radar Level Tx

Think about the difference between a shotgun and a high powered rifle.

Guided wave radar uses a principle of Time Domain Reflectometry which a radio frequency pulse is sent down a wave guide (wire) that hangs in the container that level is being measured. When the pulse reaches the level interface (surface of what is being measured) a portion of that pulse is reflected back to the transducer, which convert the time it takes for a return pulse to a level.

Free space radar is also a radio frequency device but it does not use a wave guide. It also will convert the time it takes for a return pulse and convert it to a level.

The above are just brief explanations. For more in-depth explanation, see the manufactures websites. I typically have used the Rosemount models of these instruments and if you go on the Emerson website, you can find white papers on both of these types of instruments.

Hope this helps