The distance between earth’s satellites depends on the position of the satellites in low orbit or geostationary. No, if you want to be able to use each satellite phone, each will need its own sim card. Much like an unlocked cell phone, a satellite sim card can be moved to another compatible phone, but to be able to make calls, each satellite phone will need its own sim card with an active monthly plan or prepaid airtime. Iridium offers a few prepaid airtime options from global satellite minutes to fit within any price budget and provide reliable satellite coverage!
Smaller installations using voip over a two-way satellite broadband service such as bgan or vsat bring the costs within the reach of leisure vessel owners. Internet service satellite phones have notoriously poor reception indoors, AdvanceTC though it may be possible to get a consistent signal near a window or in the top floor of a building if the roof is sufficiently thin.
If your iridium global prepaid sim card expires, your airtime will be removed from the card and you will have a 270 day refill window to purchase a refill. Outside of that 270 day window, you will need to purchase a new sim card and also receive a new number at the time you activate the new card. Many satellite phones offer data services but few offer internet access and most have very limited bandwidth.
However, many popular online functions can be carried out with an added accessory to a standard phone. Sat phones are popular for expeditions into remote areas where terrestrial cell and data services are unreliable and unavailable. Satellite phones have been around for decades, but until the launch of the iridium network, they were often only offered at an unaffordable price. Satellite phones work by connecting you through satellites positioned in low or high earth orbit. This eliminates the need of cellphone towers and allows global satellite network coverage. Additionally, the user pays same rate per minute or text message anywhere in the world. A fixed installation, such as one used aboard a ship, may include large, rugged, rack-mounted electronics, and a steerable microwave antenna on the mast that automatically tracks the overhead satellites.
The phones have connectors for external antennas that can be installed in vehicles and buildings. The systems also allow for the use of repeaters, much like terrestrial mobile phone systems.
Unlike the mobile phone and the gsm network, its efficiency does not depend on the terrestrial transmission antennas installed by different mobile operators to cover a territory. In the case of a satellite phone, transmitted and received signals pass through satellites placed in orbit around the earth.