important hardware components of weather radars and how maintenance is performed

BISMARCK, ND (KFYR) — For the past two weeks, we’ve shown you the basic operations of weather radars and how they tilt at different angles to get a full 3D picture of precipitation in the atmosphere.

But weather radars have many complex components that allow them to operate and detect precipitation 24/7/365.

Inside a special box in the center of the radar is the motor (called the azimuth drive motor) which controls the rotation or rotation of the 28 foot wide radar antenna. But you need to send the signal to the radar on something that constantly rotates 360 degrees without twisting the wires.

The way this is achieved is through the slip ring assembly. Inside the special housing in the center of the radar is a box where the signals are transferred to the rotating part of the radar by metal contact. Metal layers are stacked on top of each other with every piece of information that needs to go back to the radar on a single layer, and small metal bushes transfer the data. This also gives the rotating part of the radar power.

Higher up is the elevation motor which moves the radar up and down at the different elevation angles we talked about last week. And there are weights to perfectly balance the radar structure as a whole.

Elevation motors in the radar that control the tilt of the radar antenna(KARY)

Back on the ground, at the base of the radar, is a diesel-powered backup generator that can provide full power to the radar in the event of a mains power failure.

To maintain this complex machine, the National Weather Service employs technicians who are available 24/7 should any problems arise.

Chauncy Schultz, chief science and operations officer at Bismarck’s National Weather Service, said: “At least once a month they come out and do maintenance checks, things like changing the oil, and things like that. It’s a machine, just like your car. So we have highly trained technicians , qualified technicians who do at least monthly maintenance of the radar, more often if necessary.If something happens to break, they make an immediate repair.

Since the radar was first installed in 1994, we have only removed the “golf ball” or the “soccer ball” once. It was actually about a year and a half ago. And the reason we did it is part of what we call the “Lifetime Extension Program”. So the radar itself has been installed for 30 years now, but we have upgraded the parts. We continue to improve and extend the life cycle of radar to provide vital information.

Radome removal at NWS Bismarck
Radome removal at NWS Bismarck(NWS Bismarck)

Luckily our radar was never damaged, but other radar sites certainly were. More recently, this past summer, Rapid City, South Dakota’s radar was hit by very large hail and high winds. And like anything that could be made of fiberglass on your home, it has been damaged. And so the repair process for it takes time.

Damage to NWS Rapid City radar by hail in July 2021
Damage to NWS Rapid City radar by hail in July 2021(NWS Rapid City)

In extreme cases, with hurricanes for example, there have been cases where radars have been totally destroyed. In this case, to completely rebuild a radar, it takes a long time, many months to rebuild a radar. Fortunately, this has only happened a very small number of times in history.

NWS Lake Charles weather radar damage after Hurricane Laura in 2020
NWS Lake Charles weather radar damage after Hurricane Laura in 2020(NWS Lake Charles, Louisiana)

There’s actually a spare parts repository, if you will, to help rebuild radars if needed. But it takes time and process to completely rebuild one from scratch.

Next week on Morse Code of Weather, we’ll talk about how weather radars detect the speed and direction of particles to determine rotation in thunderstorms.

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