Keeping in touch offshore

A wide variety of choices can make selecting a voyaging communications package a daunting task. And, as if today’s choices weren’t confusing enough, there will be more choices in the near future as a variety of new satellite communications (satcom) systems become available.

The prime market for the new satellite systems is composed of non-marine users. However, voyager will benefit as satcom service providers offer communications services to niche markets such as mariners.

This process has already transpired with the American Mobile Satellite Corp. (AMSC) service. An AMSC geosynchronous satellite was placed in orbit several years ago to provide land-based users with satellite phone coverage throughout North America. And since the coverage area of the satellite (known in the satcom business as its “footprint”) extended more than 200 miles offshore, marine users were a natural secondary market. You can make a satellite phone call from your boat using the AMSC system. For coastal sailors who need voice communications and find themselves outside cell phone range, this AMSC service makes sense (more on this below).

The granddaddy of satcom systems for the mariner is the service provided by the international consortium called Inmarsat. The original Inmarsat service used analog signaling and very large (by yacht standards) stabilized dishes (diameter three feet, weight 265 lbs). This service is called Inmarsat A. The digitally based replacement to Inmarsat A is Inmarsat B (diameter three feet, weight 220 lbs). Both these systems are capable of sending voice, data, and fax transmission. However, due to their size, neither are appropriate for yachts.

Smaller than Inmarsat A/B is Inmarsat M. This service uses a stabilized dish that is 1.7 feet in diameter and weighs 50 pounds. The M service can send voice as well as data and fax. While this is a big improvement over A/B, it’s still too big for many voyaging boats.

In 1997 Inmarsat launched a new generation of geosynchronous satellites that have the capability to use a coverage technique called spot beams. This technology allows each satellite to focus smaller beams on specific areas. The increase in overall power of the satellites along with spot beam technology allows Inmarsat to offer a new service called Mini-M. It provides all the capabilities of M, but it can be used with a much smaller antenna. For example, O’Gara Satellite Systems offers a product called Boatfone. This unit has an antenna that is 8.5 inches by 9.5 inches and weighs five pounds. Mini-M also allows for voice, data, and fax connections. A Mini-M setup like the Boatfone costs roughly $7,995 for the equipment. Connection time is $3.00 a minute.

Text only

For those voyagers who have no interest in voice or fax capability, Inmarsat offers the C service. Inmarsat C terminals can send data and text messages only. For voyagers who are comfortable with Internet e-mail, this text-based system often fits the bill. It is possible to send and receive messages from the Internet. Without the need to send high-data-rate voice, Inmarsat C antennas can be small and non-stabilized (about a foot in diameter and 20 lbs in weight.) This reduces their weight and their cost. The Trimble Galaxy Inmarsat C unit has a list price of $4,999. Whereas M and Mini-M use the telephone system (the user pays for the number of minutes connected), Inmarsat C users pay for the size of their messages or the size of the data files sent. Inmarsat C rates for e-mail are 25 cents for 32 characters, or less than a penny a character. As discussed above, the AMSC satellite gives mariners within 200 miles of the North American coast, in Central American waters, and in the Caribbean voice, data, and fax capability. One of the AMSC service providers is Wavetalk, which uses equipment built by Westinghouse. You can purchase a Wavetalk setup for $4,959. Once again, you have to pay for minutes connected. Air time goes for $1.35 to $1.45 a minute.

Among the up-and-coming satellite systems is Orbcomm. This low-earth-orbit (LEO) system uses small satellites and is designed to send short text messages. The system is still in development and currently has 12 satellites in orbit. By the end of 1998, Orbcomm plans to have its complete constellation of 24 satellites in place. For voyagers who want the worldwide coverage of satcom, but aren’t interested in voice capability or in sending longer messages, Orbcomm might be good choice. The prototype Orbcomm transceiver incorporates a Magellan GPS receiver. Thus, you can send your GPS position with each message. This capability also should allow you to send your GPS position in the event of an emergency.

While Orbcomm has a system that will use small, simple satellites, Motorola’s Iridium system will take the opposite approach. Its satellites will be among the most sophisticated ever launched. Most communications satellites are so-called “bent pipes.” They receive signals from the earth’s surface and they retransmit them back down to an earth station. The Iridium satellites will have this capability as well, but they will also be able to send signals from satellite to satellite and then down to an earth station. This capability will theoretically give the Iridium system the ability to send signals via the least costly route. Iridium will use handheld satellite phones that will have worldwide coverage. Pricing for the service is not yet set.

There are several other satellite systems in the works: Globalstar, Odyssey, ICO, etc. All of these systems are scheduled to come on line within the next decade. Like AMSC, none of these systems is designed primarily for mariners, but voyagers will be able to use these services worldwide.

Advancements in HF radio

While there is a great deal of activity in the world of satcom, high frequency (HF) single sideband (SSB) has also been the beneficiary of technology advancements. One of these involves the use of new modulation schemes for sending text and data files via HF. The Clover and Pactor II techniques allow voyagers with SSB transceivers to send e-mail messages. Globe Wireless offers a Clover-based service, while PinOak Digital offers a Pactor II-based system. One of the advantages of the HF e-mail approach is that you only pay for the amount of data that is successfully sent. You don’t pay for connect time as in a telephone-type rate schedule.

While HF messaging is generally a less expensive approach than satcom, HF SSB users must do a little work to find the best frequency for making a connection. Since HF radio signals travel long distances via the phenomenon of ionospheric bounce, and since the electrical charge of the ionosphere changes during the course of each day, users must pick a frequency based on the distance between the vessel and the station they wish to communicate with, as well as the time of day. There are computer programs that will integrate the variables and suggest the optimum frequency. (Satcom systems use higher frequencies that punch through the ionosphere.)

To outfit yourself to use PinOak’s system, you need to purchase a $1,720 modem and software from PinOak and join the PinOak Association for $275. Messaging cost is 95 cents a kilobit (1,000 bits, or 125 characters). The cost for Globe Wireless is $1,500 for a modem and software. Messaging cost is 79 cents a kilobit for high-volume users.

With the new satellite systems coming on line in the next few years, communications choices for the voyager will only increase.

By Ocean Navigator