You are planning a safari to Kenya...but are anxious about the kiddies back home and the need to be contacted in an emergency. Your cell phone is not up to the task. Or you spend a good deal of time traveling back and forth to Asia on business and know your company will need your input while you are in Japan. The answer to both scenarios is a satellite phone. Journalists, people in the military, and politicians who travel the globe all know the advantages of having a satellite phone. Over eighty percent of the land on earth plus any body of water (we're talking oceans here) is without sufficient landline connection. With a satellite phone you are able to communicate with anyone with a phone number from almost anywhere. When you reach the summit of K-2 and want to do a little bragging, just pick up your satellite phone and call "the guys".
When you think satellite phone, don't expect the thin as a business card cell phone your teenager sports. Although the satellite phone has made great strides in the past few years, the sat phone more closely resembles your portable home phone or one of those clunky cell phones from fifteen years ago. That said, they can put you in touch with most anyone the world over.
Even though it is called a "phone", the satellite phone is in actuality a radio transmitter. It sends signals directly to a satellite (part of a network of satellites.).Those signals are then sent back to earth to a station. This station then directs the call to the Public Switched Telephone Network (PSTN) or to a cellular network. If you are calling from a cell or wired phone to a satellite phone, the system works in reverse. Or think of a satellite phone calling another satellite phone. The signal goes up to the satellite, down to earth, back up to a satellite and then back down to earth again. One perk of this type of satellite communication is its security, with encryption done at the station.
Although you can call or receive calls in the middle of nowhere with a satellite phone, there are downsides. Most phones need a clear "line of sight" to the satellite. So unless you set up the antenna outside, there will be no calling from your cozy bed at a hotel room. One satellite phone company, Iridium, requires the phone or at least the phone's antenna have a direct view of the satellite. Iridium's antennas are non-directional, which means they don't have to be directed right at the satellite receiving the signals. This can be helpful if you have no clue where the satellite is in the sky. Another brand, Inmarsat, has "geo-stationary" satellites. This means you have to get that antenna pointing in just the right direction with nothing but air in between for the satellite to pick up the signal (i.e., outside). Your service may also vary according to your location and the weather. An errant cloud or two may not affect your phone transmission but a solar flare might.
The phones can come with extension cords connecting the phone to the antenna, allowing the antenna to be outside and you to be inside, making the call. If you are on a cruise or on that aforementioned safari, Inmarsat provides an antenna that will find the satellite all by itself and point to it.
Another downside of the satellite phone is the limitations of bandwidth. Most people these days know the term broadband, in terms of their internet connection. Some satellite phones use a narrow band, sending along your audio signal, but they cannot handle the high bandwidth information at near the speeds you find at home. This means that you can have internet access, but for these phones that access is slow. Upgrade to say the Inmarsat mini m and get their data kit to do all your internet business on a broadband width. Satellite phone technology is advancing every day, so look for newer and better options for the world traveler.