How Satellite Phones Function

Cell phone technology has come a long way. Once large and bulky, offering only voice calls, today's smartphones are sleek and capable of almost anything you can imagine. However, they rely on cellular towers, which can be unreliable and frequently lose connection. In areas where traditional cell phones struggle to reach, satellite phones shine.

Satellite phones venture into areas where cell phones can't go. Their communication infrastructure is truly out of this world, as they connect directly to satellites in Earth's orbit, bypassing the need for terrestrial cell networks.

This technological breakthrough frees satellite phones (or 'sat phones') from the limitations faced by their Earth-based counterparts. As a result, they're the preferred option for communication in places with little or no cell service, such as remote or underdeveloped regions, countries with restricted access to mobile networks, or areas devastated by natural disasters.

In satellite communication systems, phones are often referred to as terminals instead. Regardless of the terminology, these devices are essential for connecting to a satellite.

Like cell phones, terminals offer basic calling features. While they are bulkier and heavier than cell phones, they lack the extensive features of modern smartphones. Instead, a satellite phone is a simplified device primarily used for making calls or sending short text messages.

You might be curious how a satellite phone differs from the GPS feature many smartphones have. GPS isn't designed for calls or texts—it's simply for locating your position. With GPS, your phone can guide you to your destination or help you find nearby places. A satellite phone, however, allows you to make calls and send data using satellite communication.

Read on to discover how satellite systems can sometimes outperform cellular networks and why not all satellite phone configurations are created equal.

A Satellite by Any Other Name

Satellite phone systems function in distinct ways depending on the technologies utilized by each provider. Some companies choose geosynchronous satellites, while others rely on low Earth orbit (LEO) systems. Every setup, or constellation, has its own strengths and weaknesses.

Geosynchronous satellites (also known as GEO orbit or high Earth orbit satellites) track the Earth's rotation, ensuring they stay in a fixed position in the sky. These satellites orbit at an altitude of approximately 22,000 miles (35,000 kilometers) and remain above the equator.

These massive, powerful satellites can cover a vast area of Earth's surface. With just three or four satellites in their constellation, a company can offer service to nearly the entire globe. Designed to support large data volumes, these satellites facilitate voice calls, video streaming, file sharing, texting, television, and much more. Inmarsat and Thuraya are well-known companies using geosynchronous configurations.

One drawback of geosynchronous satellites is the transmission delay caused by their high altitude, which results in a delay of about 250 milliseconds one-way or a quarter-second round-trip. As a result, you might experience a slight pause before the other person responds, or you may hear an echo, which can be quite frustrating.

Due to their limited numbers, these satellite networks are more vulnerable to outages. If one satellite needs repairs or malfunctions, large areas of the world may lose service until the problem is resolved. Additionally, because geosynchronous satellites are positioned mainly above the equator, they offer little coverage near the poles.

A key drawback of geosynchronous systems is their size. To connect with these satellites, you need a device roughly the size of a laptop, much of which consists of a directional antenna. You may also need to adjust the antenna and aim it at the satellite to get the best reception.

On the following page, you'll explore more about the advantages and costs involved in choosing a particular satellite phone technology.

Leaping into LEO

LEO satellites orbit at much lower altitudes, up to 930 miles (1,500 km), and are operated by companies like Globalstar and Iridium. While geosynchronous satellites are the giants of the industry, LEO satellites are the more nimble players. They are smaller, lighter, and much more numerous.

Due to their low orbital altitude, LEO networks may require up to 60 satellites to cover most of the Earth's surface. As these satellites travel at speeds of around 17,000 miles (27,359 kilometers) per hour, completing an orbit in approximately two hours, you may find yourself within range of two or more at any given moment.

The fast, low orbits of LEO satellites ensure reliable coverage for much of the globe. So, if you're a researcher facing an emergency in Antarctica, you can count on LEO satellites for your communication needs.

LEO satellites stand out for their exceptional call quality, minimal delays (about 50 milliseconds one way), and superior reliability. They also consume less battery power, which means your device won’t drain as quickly as one using a geosynchronous satellite. However, their data transmission rate is slower, around 9,600 bits per second, which means streaming video like YouTube is off the table.

One of the biggest advantages of LEO satellites is that they don't require large antennas on your device. Instead, LEO phones are typically only slightly larger than a regular smartphone, making them convenient and portable enough to fit in your pocket.

Regardless of whether you're using a geosynchronous or LEO network, your phone needs an unobstructed line-of-sight to the satellite for optimal service. So, if you're indoors, stepping outside may be necessary to make a call.

With a geosynchronous satellite network, maintaining line of sight can be a challenge, particularly in areas with dense forests or mountainous terrain where visibility is limited. However, with a LEO network, you'll have multiple chances to connect as satellites pass overhead, though these opportunities are often brief, lasting only a few minutes.

What if you're in a location with poor reception and someone on the other side of the world urgently needs to reach you? As your signal fluctuates, you'll get a pager notification alerting you to the incoming request. You can then move to an area with better reception to complete the call.

If you find yourself in a war-torn region, it's essential to stay cautious and aware of your surroundings. Keep reading to learn why using a satellite phone in some areas could pose health risks.

Sat Phone Smackdown

Satellite phones are governed by a unique set of regulations, not only from a technological perspective but also politically. Governments that prefer to control their citizens' communication methods tend to have a strong dislike for satellite phones.

During peacetime, many government agencies have easy access to monitor cell phone communications. In times of conflict, these agencies can even disable cell towers to disrupt or sabotage wireless communication; similar controls are often applied to various types of Internet services.

However, satellite phones operate differently. They bypass ground-based communication towers, making them harder to manipulate or monitor compared to regular cell phones. Even though a determined regime might try to jam satellite signals, such efforts are often only temporarily successful.

As a result, some oppressive governments have made satellite phones illegal. While they can't eliminate the technology, they can make people afraid to use it.

For instance, in Bangladesh, Anup Chetia was sentenced to prison for possessing a satellite phone, which he used for various anti-government activities [source: Hossain]. In North Korea, while government-issued cell phones are allowed (and monitored), satellite phones are strictly prohibited [source: Lee].

When the Arab Spring spread to Syria and the country descended into civil war, the government cut off many forms of cell and internet communication. This forced rebels and activists to rely on satellite phones. In fact, demand for these devices surged so dramatically that Thuraya, the region's main provider, reported a shortage of handsets [source: Hamid].

While using a satellite phone might allow for free-roaming calls in a conflict zone, it doesn't make you undetectable. Even if governments can't block your calls, they can track the location of satellite phone signals unless the system is equipped with signal-scrambling features.

Satellite phones aren't just vulnerable to human interference; they're also at the mercy of nature's forces. Just like cell phones and other radio-based communication systems, satellite phones can be rendered useless by powerful solar flares and other natural events.

As you'll discover on the next page, solar flares and military regimes might not be your biggest concern when it comes to satellite phones. Instead, the cost of these devices could leave a dent in your bank account.

Sat Phones Flatten Wallets

In comparison to the widely-used cell phones, satellite phones are considered a niche technology. Like many extraordinary gadgets, they are pricier to use than the more common mobile phones. Costs can differ greatly depending on whether your provider relies on geostationary or LEO satellites.

Regardless of your chosen provider, the handsets and terminals are always more expensive than typical cell phones. At a time when many cell phone providers practically give away phones, satellite phones generally cost at least a few hundred dollars. In 2013, for a decent LEO handset, you could easily be looking at around $1,000. If you're in the market for a briefcase-sized geosynchronous phone, prepare to spend several thousand dollars.

However, that initial investment is likely just the tip of the iceberg. To make calls, you’ll find yourself spending a significant amount of money per minute. Rates can vary greatly depending on the provider and the destination of your call, but it’s common to pay about $1 per minute, and the same amount for a single text message. Receiving calls is even more expensive, especially if the call is coming from a landline. In such cases, you could end up paying several dollars per minute. And if you're calling a phone on another satellite network, the costs can climb even higher.

Satellite providers are well aware of the high costs associated with their services compared to standard mobile phone plans. That’s why they often offer pre-paid plans for minutes. This way, you're less likely to rack up astronomical bills since you've already paid for the minutes upfront.

You might be able to avoid some calling charges by opting for a dual-mode sat phone. These phones work with regular cell networks and, by default, route your calls through them. However, when you're out of range of cell towers, the phone switches to satellite mode, ensuring you'll almost always have service.

Alternatively, before committing to a purchase, consider renting a satellite phone. You can rent a basic terminal or handset for just a few dollars per day. For short trips or testing out the service, renting can be a more budget-friendly option.

Despite their high prices, satellite phones serve a crucial role in today's world of constant connectivity. Without them, many remote regions would remain unreachable by phone. When the need to make an important call arises, no price is too steep to pay.