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High-Frequency Radar

High-Frequency Radar

New to the Great Lakes, high frequency radar gives us a live snapshot of lake surface currents, 24 hours a day.

High Frequency Radar
Near-Mackinac-Island-web

HF radar measures surface currents like no other platform can: over large areas.

When studying currents, researchers are typically limited to a device that measures only one point in the water.

By capturing extremely detailed, near-surface water direction and speed information, this platform allows observers to:

  • Locate people or pets during search and rescue operations
  • Track vessels
  • Monitor movements of hazardous spills or harmful algal blooms
  • Understand how water moves through complex waterways, like in the Straits of Mackinac

Photos by Nathan Shaiyan, Michigan Technological University, unless otherwise noted.

HF radars are shore-based remote sensing systems made up of antennas, generally used in pairs and placed close to the water’s edge.

The antennas send out high-frequency radio waves that bounce off the water’s surface and back to the antenna. By measuring how the waves bounce back, the radar is able to create a map detailing the speed and direction of surface currents.

Because saltwater allows HF radar to work over much larger areas, coastal waters have long benefited from HF radar, but the Great Lakes are just beginning to use it. Even the reduced range, reaching 10-15 miles in some tests, can be enough for many areas.

The first HF radar installation will be in the Straits of Mackinac where, operated by Michigan Technological University (MTU) researchers Lorelle and Guy Meadows, a single radar pair has been able to cover the straits on one side of the Mackinac Bridge.

Early tests shows the flow of water through the western end of the Straits of Mackinac. Photo by Lorelle Meadows, Michigan Tech. University
High Frequency Radar from below

Pair distance: 6.6 kilometers (4.1 miles)

Total area covered: 20 square kilometers (7.7 square miles)

Radar: 42 Mhz

Transmit power: 40 watts

Map refresh: every 30 minutes

Seagull

High-frequency radar will be available on Seagull.

GLOS