What is the purpose of housing Doppler Radar in a Dome?

Question

i'm not asking why is it dome shaped, i am asking why does it have to be covered up?

Other radars seems to operate fine without a covering why is Doppler so special .. can it serve its purpose without the dome?

Answer 1

It is for protecting the radar antenna. It is the same principle they use on aircraft weather radars. The radome prevents damage from the elements. This way they can protect the antenna without having to engineer a weather-proof one for much more money.

Answer 2

SIMPLE -- to protect the radar eqp

Answer 3

The dome itself mostly contains air and is actually just a protective housing for the much more familiar-looking 28-foot radar dish which it encloses. Within this protective housing, the radar dish constantly rotates just as all other radars we have seen on top of airport control towers, navy ships, etc.

So, while NEXRAD sites may look very different from other radar antennas that we have seen, it's really the same idea. They just happen to have comparatively big dishes enclosed in a big white ball on the top of a tall tower.

Answer 4

The dome is aerodynamic,not for the radar but for the plane.

Answer 5

The dome is simply to protect the antenna from the weather.  Larger antennas like Airport Surveillance Radar are left exposed because it would cost too much to build a dome for that size antenna.  It's cheaper to do a little more maintenance on the antenna.

Answer 6

What Dan said about aerodynamics, but I must say it protects the antenna a well. Not so much from the elements, they can be weatherized to and extent, but from the wind blowing along at hundreds of miles an hour.

Thanks for the thumbs down!!!!!!!!!!!!!!

Answer 7

Where did you get the impression it has a dome?  Doppler unlike pulsed radar only requires a fixed position small TxRx probe.  Navigational Doppler uses a flat disc cover about eight inches in diameter.

Doppler radar functions on frequency shift like the change in sound when a train or car approaches the listener.  As it approaches the frequency increases and decreases as it moves away.  Most Highway Patrol Cars today incorporate Doppler Radar.  Have you seen any with a dome?

Since you asked this question in Aircraft I assumed you were referring to Aircraft Doppler, DNS.  If you are talking about Doppler used in weather observation that is a different issue for two reasons.  

1.  The distance of detection is significantly greater.  (DNS operates >70,000 ft.) Weather Doppler operates up to 110,000 ft at extremely long range.  And the targets are finite compared to DNS target of mother earth.  Thus a larger antenna is required to compensate for less dense target and signal attenuation.

2.  Where DNS looks in one direction, down, all the time, Weather Doppler has to look 360 degrees at different elevations.

The large antenna has to rotate and change it's elevation.  Doesn't it make sense to enclose the mechanism to protect it from weather, birds and other wildlife?  All large disc Radars with variable elevation have domes.  When you see an enclosed antenna rotating it's strictly navigation or weather with no elevation options.

Incidentally weather Doppler is still a function of movement, or frequency shift, but it can detect less dense targets.