In Iridium Satellite Systems, which frequency band is designated for ground-based users?

The correct answer is that the frequency band designated for ground-based users in the Iridium Satellite System is the L-band, specifically within the range of 1616 - 1626.5 MHz. This frequency band is chosen because it allows for effective communication between the handheld devices used by ground personnel and the satellite network. The L-band frequencies are advantageous for satellite communication due to their ability to penetrate foliage and urban structures, providing robust signal reliability in various environments.

In addition, the L-band is widely used in mobile satellite communications, making it a familiar and established choice for devices that require real-time voice and data services. By utilizing this specific frequency range, Iridium can efficiently support a global network that caters to users who require reliable communications, including those in remote areas where other forms of communication may not be viable.

Other frequency options mentioned do not serve the purpose of ground-based user communication in the Iridium system. Instead, they are used for different applications or other types of satellite communication.