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Name: Unknown
Status: other
Age: 30s
Location: N/A
Country: N/A
Date: 1999
Question:
Are police radar detectors affected by dense fog and or rain? How and what are the affects.

Replies:
Dear Rocket-

Your question about police radars and how weather affects them is a good one. Weather has almost no effect on the operation of those radars.

What a radar "sees" depends on the character of the radar beam. In general, the higher the frequency of the radar beam, the smaller the particles it can detect. Radars designed to detect moving vehicles use frequencies that are not reflected by small moisture droplets such as fog and clouds, or even precipitation.

Very heavy rain can reduce the range of all radars, (an effect called "attenuation"), due to the signal being absorbed by the precipitation. In this case, weather conditions usually cause motorists to slow down to well below the speed limit anyway.

Wendell Bechtold, Meteorologist
Forecaster, National Weather Service
Weather Forecast Office, St. Louis, MO


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