Satellite Phones & Mobile Phones

Satellite phone and Cellular phones are wireless devices. They almost look alike. But the way they work is totally different. Cellular phones working method is cell based. That is why they are called cellular phones. The whole network area is divided into small areas. And in each area an antenna is installed. These are also called towers. When a cellular phone is moving, it keeps entering from one cell to another. When it crosses the border of one cell, the phone sends a signal to the MTSO (Mobile Telephone Switching Office). With the help of control channel the database of the MTSO relocates the phone in a new cell or area. The MTSO and Public Switched Telephone Network (PSTN) coordinate to handle cellular calls.

But in the contrary Satellite phones use Low Earth Orbiting (LEO) satellites. With the turning on of the satellite phone a signal goes up to the any number of satellites of a group with whom the phone is registered. When a person makes a call from the handset, a signal goes to the near by orbiting satellite. The satellite connects to the gateway or ground station. Then the gateway takes the call to the destination. The call can be directed to the landline, cellular phone or PSTN. Any of the landlines, cell phone or PSTN can also call a satellite phone. In the case of satellite phones the gateway takes care of calls not cells as in the case of cellular phones. If a satellite phone calls another satellite phone, the call reaches a ground station through a satellite. Then it goes up to the air to a satellite and then the call reaches the destination phone. So the gateway processes the switching of calls not the satellite.

Mobile phones offer some really impressive benefits especially to world travelers. But on the other hand, they also present certain challenges, like when travelling from one place to another will they even work properly. This is due to the incompatible and differing nature of the various mobile phone systems, which often define the entire continents or regions.

In contrast to the conventional mobile phones, satellite phones connect to orbiting satellites instead of the terrestrial cell sites. So whether you’re reporting news from the mountains or just keeping in touch with your office during a trip, satellite phones can be simply the choice for you when you absolutely need a phone in the far off places of the world.

Like with most satellite communications you need line-of-sight communication in satellite phones as well. So when using a mobile satellite phone you need at least about 80% of the view of the sky to receive good service. Obstructions such as buildings, trees and vehicles roof can block the signals from the satellite from reaching the device. So the more you’re cut off from the view of the sky, the more possibility of having dropped calls and no service.

A satellite phone utilizes two sorts of networks basically:

Geosynchronous orbit services

Low earth orbit services

A geosynchronous orbit satellite completes one revolution in the same time that the earth completes one rotation. It rotates with the earth and thus appears to remain fixed, or stationary, over a particular location. It offers a greater bandwidth compared to low earth orbit services.

A low-Earth-orbit satellite, or LEO, circles the planet in 90 minutes to 2 hours. LEOs allow for use of smaller dishes and handheld devices, so they are well-suited for interactive conferencing. However, because a LEO remains above the local horizon for about only 20 minutes, large numbers of these satellites, in several different orbits, are required to maintain service. Generally LEOS offers a greater battery power life compared to geosynchronous services.

Currently, there two companies that are powered by LEO and that offer the satellite phone services, namely: Iridium and GlobalStar.

Iridium uses a network of 66 satellites that orbit the poles they travel from pole to pole giving coverage practically everywhere on the globe. If an Iridium user phone is calling another Iridium user phone then the call is not sent to the gateway and it’s entirely handled by the networked satellites.

Globalstar uses a network of 48 satellites that orbit the central hemisphere of the earth covering over 120 countries. If a phone user of the Globalstar is calling another Globalstar phone user the call goes to the ground station then back up the satellite network then down to the other Globalstar phone.

In near future, Globalstar plans to send their satellite signals over terrestrial cellular towers allowing the signals to break through obstacles like building and vehicles. So a satellite phone would be in terrestrial mode when line-of-site to the satellite is blocked by an obstacle and when the phone gets hold of line-of-site to the satellite network then the phone would be switched to the satellite mode.

Although satellite phone services can be really expensive and there are fewer providers to choose from the satellite communication industry is a growing and ever changing field. Over the last few years there has been a remarkable growth in the satellite phone market and the future for the satellite phones looks really bright. As the technology progresses customers will enjoy additional services offered never before.

Iridium 9555 Antenna

If you are using the new Iridium 9555 then you will have noticed how fantastic the new antenna is. Much smaller than the previous version. More information about the antenna below:

Sarantel develops and manufactures advanced miniature filtering antennas for mobile, wireless and handheld devices. Iridium is a pioneer in the satellite communications industry and is the only mobile satellite services (MSS) company offering truly global, pole-to-pole coverage.

The Iridium 9555 represents a dramatic step forward in innovation and usability for handsets in the MSS sector. Users will benefit from a host of innovative features, such as a brighter screen, a speaker phone, short messaging service (SMS) and email capabilities, an upgraded mini-USB data port, an internal antenna and significantly reduced form factor. It is also programmable in 14 languages.

"The ability of Iridium to reduce the antenna size, without sacrificing performance, was a critical design element for this revolutionary new handset," said David Schoen, chief technology officer, Iridium. "Sarantel responded to our challenge by providing Iridium with a highly innovative, technically advanced design for the 9555 antenna. They proved to be a superb technology partner, producing a creative, cost-effective and performance-driven solution."