What is the orbiting altitude of the Iridium satellite communications system?

485 miles.

The Iridium system has been designed to cover at least one satellite in every area on the planet. So, anywhere you are on Earth, you can use a handheld to call, but you need to be outside, and not inside of a building.

The 485 miles or 780 kilometers orbit are in the polar orbit region.

For more info, see the Road Post site, for the article Iridium Satellite Constellation

Also, see Wikipedia's article on Iridium satellite constellation

For more info on IRIDIUM© system, please see the main site page.

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What frequency band is used by the Iridium system for telephone and messaging?

1616 -1626 MHz.

For more information, please see Apollo Sat site, for the article on Iridium Satellite System Operation, technical specifications under heading Iridium satellite summary

Also, see Wikipedia's article on Iridium satellite constellation

For more info on IRIDIUM© system, please see the main site page.

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What services are provided by the Iridium system?

Digital voice and Data at 2.4 kbps.

For full listing of current services, please see the IRIDIUM© site, All Services page.

For more info on IRIDIUM© system, please see the main site page.

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Which of the following statements about the Iridium system is true?

There are 48 spot beams per satellite with a footprint of 30 miles in diameter.

The IRIDIUM© system uses antennas that provide 16 spot beams, totaling 48 spot beams on each satellite. A spot beam functions similarly to a cell in a cellular network. Each spot beam works on a slightly different frequency.

The answer states "30 miles in diameter." The Satellite Phone Review site, section Satellites states that:

"Each satellite can project 48 spot beams on the Earth’s surface. The size of each spot beam is approximately 250 miles in diameter and the satellite’s full 48-beam footprint is approximately 2,800 miles in diameter. All spot beams and satellite footprints overlap."

For more information, please see The Satellite Phone Review site, for the article How Iridium Works

Also, see the graphical map of the Iridium Service Coverage Map on the Static Mackaycomm site.

Please see Wikipedia's article Iridium satellite constellation

For more info on IRIDIUM© system, please see the main site page.

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What is the main function of the COSPAS-SARSAT satellite system?

Monitor 406 MHz for distress calls from EPIRBs.

For more information, please see the Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA) site for the article on Cospas-Sarsat System Overview

Also, the main COSPAS-SARSAT site, main page

For excellent and highly illustrated overview, please see EO Portal Directory site, for the article COSPAS-SARSAT (International Satellite System for Search and Rescue Services)

Please see Wikipedia's article on International Cospas-Sarsat Programme

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How does the COSPAS-SARSAT satellite system determine the position of a ship in distress?

By measuring the Doppler shift of the 406 MHz signal taken at several different points in its orbit.

For more information, please see the Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA) site for the article on Cospas-Sarsat System Overview

Also, the main COSPAS-SARSAT site, main page

For excellent and highly illustrated overview, please see EO Portal Directory site, for the article COSPAS-SARSAT (International Satellite System for Search and Rescue Services)

Please see Wikipedia's article on International Cospas-Sarsat Programme

See YouTube video from the MZO channel called How does COSPAS-SARSAT work to find 406Mhz emergency beacon?

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