A fully equipped nav station includes communications gear and often a computer.
Today, the only real limitations to high-speed digital communications for vessels at sea are the size and cost of the onboard equipment and the per-minute or per-byte cost of sending and receiving data. Several satellite communication systems capable of handling voice, fax and data in these coastal waters are suitable for use on even modestly sized yachts. Hand-held satellite telephones using either the Globalstar or Iridium networks can, in addition to voice, handle digital data at modest speeds. Globalstar has widespread coverage in many areas of the world. Iridium has worldwide coverage. Inmarsat, the company that provides worldwide satellite communication service for commercial and recreational vessels offers both a version certified to Global Marine Distress and Safety System standards as well as a non-GMDSS version of their Inmarsat-C packet data system. The non-GMDSS service can provide vessels of any size (some as small as rowboats) a very effective means for sending and receiving email messages and, if desired, automatically transmitting GPS-derived vessel position reports. It will be necessary to subscribe to some type of service contract to use any of the packet data systems. Inmarsat-C, however, is not capable of accessing the Web; it is limited to sending and receiving email and data files. Inmarsat’s mini-M service provides voice communication at 4.8 kilobits per second (Kbps) and fax and data communication at 2.4 Kbps. As for virtually all geostationary satellite-based systems, the precise coverage area for the mini-M systems is a function of the size of the onboard antenna and the location of the vessel with regard to the satellite’s use of spot beams that increase both the strength of the signal delivered to the earth’s surface and the ability of the satellite to “hear” the vessel’s signal. The most capable of Inmarsat’s services — the new Fleet F77 system, intended for use by commercial vessels and installed on large yachts — can handle digital data such as ISDN upload or download at speeds up to 64 Kbps. The F77 mobile packet data service (MPDS) provides continuous connection to the Internet via satellite, while charging only for the amount of data actually exchanged. However, even the 64 Kbps data transfer rate offered by Fleet F77 does not provide what most Web surfers want — truly broadband data rates well above 100 Kbps. In addition, the 33-inch-diameter radome that houses the stabilized F77 antenna is too large for yachts less than about 55 feet in length. (Although we have seen some devoted communicators whose rather small boats looked more like antenna farms than sailing vessels.) In addition to the Fleet F77 service, Inmarsat offers two other services in the Fleet line: Fleet F55 and Fleet F33. The Fleet F55 service provides a data rate of 64 Kbps, while the rate for Fleet F33 is 9.6 Kbps. Using TV satellites Sailors willing to limit their appetite for high-speed Internet access to waters within about 200 miles of the North American coast and most of the Caribbean may find the answer to their needs in the KVH tracNet system. The tracNet system uses transponders on the high-power DVB TracVision satellite to downlink information to users via the DirecPC system. Within the primary coverage area of the satellite’s antennas, the high power of the signal from the satellite allows the use of relatively small TracVision stabilized TV antennas. As with any satellite link, the maximum communication speed is largely determined by the signal-to-noise ratio achieved by the combination of available transmitted power at the location of the terrestrial user and the sensitivity of the antenna/receiver unit. Located in its geostationary orbital position at 91° W, the DVB satellite can send mobile DirecPC data at speeds up to 400 Kbps to 18-inch-diameter antenna systems over most of the North American continent and adjacent offshore waters to about 100 miles off the coasts. The 400-Kbps coverage can be extended farther from land with the use of larger antennas, 24-inch or 32-inch diameter. Once beyond the primary coverage area for each size antenna, communication is at a nominal 56 Kbps, using KVH’s velocity acceleration software. Asymmetrical data rates For most users, the satellite communication link does not need to offer identical data exchange rates in both directions. A relatively slow uplink rate usually suffices, even when surfing the Web. In the tracNet system, the route used to uplink data, including email and requests for display of specific websites, varies with the location of the vessel. Whether at sea or in areas served by cellular telephones or telephone land lines, when offshore or when located in near-shore areas devoid of cellular phone service, data is uplinked to DirecPC’s servers via the Globalstar satellite system. When in range of suitable cellular phone service, the system will automatically use its built-in digital cellular telephone modem. Alternately, a telephone modem can be used when the vessel is at a dock served by a telephone landline. Uplink data speed is highest, up to 56 Kbps when using the landline phone modem. Cellular modem speeds can be as high as 14.4 Kbps. Uplink speed via Globalstar is 9.6 Kbps. Use of the Globalstar bent-pipe satellite communication system for wireless data uplink provides an advantage when the vessel ventures beyond the coverage area of the DirecPC satellite signal. In these areas, which extend beyond 200 miles from shore, the system uses the Globalstar path for both uplink and downlink at 9.6 Kbps. This speed is sufficient for efficient email communication with the possibility of voice over Internet protocol (VOIP) if desired. TracNet’s router server software is compatible with various forms of the Windows operating system software. Installation of the tracNet system is relatively simple and should be within the capability of many boat owners. The system is composed of one of KVH’s automatic TV tracking antennas with its video receiver and amplifiers; a mobile Internet router/server; the separate tracNet uplink antennas, housed in their own radome-like enclosure; and whatever computers and television sets the owner wishes to use. The uplink radome houses both the Globalstar and the digital cellular modem antennas and their associated amplifiers and transmitters. Globalstar’s use of low-earth-orbit satellites eliminates the need for a tracking antenna for the uplink. Data from the receiving antenna flows to the system’s mobile Internet router/server, which — mounted below deck — provides both wired 10/100 Ethernet and 802.11b wireless connection to up to five simultaneous users. The ability of the tracNet system to download data at up to 400 Kbps provides both speed and economic advantage. Examples cited by KVH are based on a $0.79 per-minute satellite-use charge. At that rate, the cost to download a 1-megabyte (MB) file is $0.26 (accomplished in 0.3 minutes). By comparison, downloading the 1-MB file using a digital cellular modem operating at 14.4 Kbps at a per-minute cost of $0.40 would cost $3.70 and take nine minutes. The cost ratio against other alternatives, such as Globalstar, Iridium and Inmarsat-B, are equally compelling. Horsepower, or in this instance, bandwidth, is hard to beat. Improved data compression KVH offers a data-compression system, Velocity Acceleration, that can be used to increase the effective information transfer rate. The speed increase achieved depends on both the user’s willingness to sacrifice detail in images and compatibility with the Internet service provider. Once installed on the user’s PC, the system operates in background for both uplink and downlink communications except when the operator determines that the type of data being transferred requires uncompressed handling. The performance tuning window provides an excellent visual guide to the amount of image degradation that may result from use of varying degrees of compression. The system designers recommend use of the medium-speed (good-quality) setting when communicating on a broadband link and the high-speed (low-quality) mode when on a standard narrowband link. The cost per megabyte must be viewed in the context of the service plan elected by the boat owner. As with most such services, there is a one-time activation fee of $100. Growing use of the tracNet system has led to a number of reasonably attractive service package offerings. These vary from an open-rate plan costing $99 per month with a $0.99-per-minute connection charge to a $490-per-month Platinum Turbo plan that includes 1,500 minutes of Internet connection for an effective per-minute cost of $0.33 if you use all the minutes. Additional minutes on this plan are billed at $0.69 per minute. Clearly not cheap, but for anyone who needs the data-transfer power the system offers, it can be a bargain. Billing is to the nearest minute. Since the customer is billed for the entire time the channel is open, the software will terminate the connection whenever data is not being downloaded. Files are cached, allowing their content to be perused at leisure. The tariff provides for a reduced-cost sustaining charge of $39 per month for periods when the boat is not in use. Another marine broadband firm called TeleSea offers an Internet access service called TeleSea Blue. The base service that can provide data at speeds of 512 Kbps downlink and 128 Kbps uplink using an actively stabilized dish antenna. The company uses transponders on a commercial communications satellite called AMC-6 that hangs over North America and can reportedly provide service over the entire North American landmass and out into the ocean areas along the coasts. According to Forrest Wheat, CEO of Wheat Wireless, which owns TeleSea, the service is available, “way out into the Pacific, all over the Caribbean.” In the North Atlantic, Wheat said the TeleSea service was designed to be available as far east as Bermuda, although the company had not yet tested in Bermuda. This system is not for smaller boats; it is a big-boat approach for serious Web users. However, the availability of two such broadband systems, tracNet and TeleSea, is an interesting sign that Web access may become more widely available in the future for the medium-sized voyager. During our investigation of the tracNet system, we looked into another new KVH communication product, eTrac. This system uses the venerable Inmarsat-C packet data system. Inmarsat-C is particularly well suited for use on small vessels and is also installed on most large ships where it is a part of the GMDSS suite. KVH, working in cooperation with the Danish company Thrane & Thrane, recently introduced a non-GMDSS version of the onboard equipment, called Capsat-C. Although using this system for communication may seem painfully slow, with a receive data rate of 600 bps and transmit rates of 300 and 600 bps, it is more than adequate for most email requirements, and it provides a maximum message length of at least 10 Kb. The equipment is the ultimate in simplicity, consisting of a fixed antenna measuring only 5.75 inches high and 6.4 inches in diameter, an interconnection breakout box, and requiring a computer capable of running the Windows operating system. The antenna contains an internal 12-channel GPS receiver that can be used to transmit vessel position information automatically at programmed intervals — once per hour, once every five hours or once per day. Connected to a compatible laptop computer, the system can send and receive email at a cost of about $0.01 per character. The system allows selection of the number of bits used to identify each character. Eight-bit encoding allows all normal character sets to be used, including messages that include HTML. Seven-bit and five-bit encoding restricts the character set while reducing per-message charges. The cost of sending automatic position reports is less than for normal message traffic since special encoding is used to transmit the information. As with all other Inmarsat-based systems, eTrac must be registered as a mobile earth station (MES). The remainder of the registration process includes identifying the land earth station (LES) designated to handle your data and the data network identity (DNID). Once through that acronym puzzle, things really are quite simple. Power consumption is very low, only 1.8 watts in receive mode and 23 watts when transmitting continuously. Power consumption per day when used for automatic periodic position reporting is 0.078 watts when reporting hourly, 0.025 watts for reports sent every five hours and 0.011 watts for a once-a-day position report. These power levels can be supported easily by a small solar panel charging a 12-volt battery. The bottom line is that by using today’s technology, almost any boat longer than about 25 feet can enjoy communications and entertainment facilities available only to large ships just a few years ago. The growing availability of both new and used Globalstar and Iridium hand-held satellite phones and various service plans can make them an attractive way to explore onboard satellite communication without making a multi-thousand–dollar commitment to a fixed system. Contributing Editor Chuck Husick is a sailor, pilot and Ocean Navigator seminar instructor. He lives on the west coast of Florida. For more information on the tracNet testing process, please view this issue's Web Extras
In addition to the Fleet F77 service, Inmarsat offers two other services in the Fleet line: Fleet F55 and Fleet F33. The Fleet F55 service provides a data rate of 64 Kbps, while the rate for Fleet F33 is 9.6 Kbps.
Courtesy Thrane & Thrane
Using TV satellites
Sailors willing to limit their appetite for high-speed Internet access to waters within about 200 miles of the North American coast and most of the Caribbean may find the answer to their needs in the KVH tracNet system .
The tracNet system uses transponders on the high-power DVB TracVision satellite to downlink information to users via the DirecPC system. Within the primary coverage area of the satellite's antennas, the high power of the signal from the satellite allows the use of relatively small TracVision stabilized TV antennas. As with any satellite link, the maximum communication speed is largely determined by the signal-to-noise ratio achieved by the combination of available transmitted power at the location of the terrestrial user and the sensitivity of the antenna/receiver unit. Located in its geostationary orbital position at 91� W, the DVB satellite can send mobile DirecPC data at speeds up to 400 Kbps to 18-inch-diameter antenna systems over most of the North American continent and adjacent offshore waters to about 100 miles off the coasts. The 400-Kbps coverage can be extended farther from land with the use of larger antennas, 24-inch or 32-inch diameter. Once beyond the primary coverage area for each size antenna, communication is at a nominal 56 Kbps, using KVH's velocity acceleration software.
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KVH's tracNet unit for accesing the Web. Downlink is via the antenna shown. Uplink is accomplished via cell phone or Globalstar satellite. Boats already equipped with KVH TracVision TV systems, including the low-profile C3 (14.5 inches high) and the L3, S3 and G4, can equip for the tracNet system by adding the mobile Internet router/server. Vessels equipped with the larger antennas capable of more precise satellite tracking, such as the KVH G6 antenna (26.2 inches in diameter and 27.1 inches high), and incorporating the KVH GyroTrac heading sensor, have the capability to better track the geosynchronous satellite. The result is increased antenna gain that allows these vessels to obtain service farther offshore. (The GyroTrac sensor used to provide precise heading information to the antenna-stabilization system also provides a superior source of vessel heading information for all other onboard needs, including the ship's autopilot.)
Asymmetrical data rates
Courtesy Thrane & Thrane
For most users, the satellite communication link does not need to offer identical data exchange rates in both directions. A relatively slow uplink rate usually suffices, even when surfing the Web. In the tracNet system, the route used to uplink data, including email and requests for display of specific websites, varies with the location of the vessel.
Whether at sea or in areas served by cellular telephones or telephone land lines, when offshore or when located in near-shore areas devoid of cellular phone service, data is uplinked to DirecPC's servers via the Globalstar satellite system. When in range of suitable cellular phone service, the system will automatically use its built-in digital cellular telephone modem. Alternately, a telephone modem can be used when the vessel is at a dock served by a telephone landline. Uplink data speed is highest, up to 56 Kbps when using the landline phone modem. Cellular modem speeds can be as high as 14.4 Kbps. Uplink speed via Globalstar is 9.6 Kbps. Use of the Globalstar bent-pipe satellite communication system for wireless data uplink provides an advantage when the vessel ventures beyond the coverage area of the DirecPC satellite signal. In these areas, which extend beyond 200 miles from shore, the system uses the Globalstar path for both uplink and downlink at 9.6 Kbps. This speed is sufficient for efficient email communication with the possibility of voice over Internet protocol (VOIP) if desired. TracNet's router server software is compatible with various forms of the Windows operating system software.
Installation of the tracNet system is relatively simple and should be within the capability of many boat owners. The system is composed of one of KVH's automatic TV tracking antennas with its video receiver and amplifiers; a mobile Internet router/server; the separate tracNet uplink antennas, housed in their own radome-like enclosure; and whatever computers and television sets the owner wishes to use. The uplink radome houses both the Globalstar and the digital cellular modem antennas and their associated amplifiers and transmitters. Globalstar's use of low-earth-orbit satellites eliminates the need for a tracking antenna for the uplink.
Data from the receiving antenna flows to the system's mobile Internet router/server, which &mdash mounted below deck &mdash provides both wired 10/100 Ethernet and 802.11b wireless connection to up to five simultaneous users. The ability of the tracNet system to download data at up to 400 Kbps provides both speed and economic advantage. Examples cited by KVH are based on a $0.79 per-minute satellite-use charge. At that rate, the cost to download a 1-megabyte (MB) file is $0.26 (accomplished in 0.3 minutes). By comparison, downloading the 1-MB file using a digital cellular modem operating at 14.4 Kbps at a per-minute cost of $0.40 would cost $3.70 and take nine minutes. The cost ratio against other alternatives, such as Globalstar, Iridium and Inmarsat-B, are equally compelling. Horsepower, or in this instance, bandwidth, is hard to beat.
Improved data compression
KVH offers a data-compression system, Velocity Acceleration, that can be used to increase the effective information transfer rate. The speed increase achieved depends on both the user's willingness to sacrifice detail in images and compatibility with the Internet service provider. Once installed on the user's PC, the system operates in background for both uplink and downlink communications except when the operator determines that the type of data being transferred requires uncompressed handling. The performance tuning window provides an excellent visual guide to the amount of image degradation that may result from use of varying degrees of compression. The system designers recommend use of the medium-speed (good-quality) setting when communicating on a broadband link and the high-speed (low-quality) mode when on a standard narrowband link.
The cost per megabyte must be viewed in the context of the service plan elected by the boat owner. As with most such services, there is a one-time activation fee of $100. Growing use of the tracNet system has led to a number of reasonably attractive service package offerings. These vary from an open-rate plan costing $99 per month with a $0.99-per-minute connection charge to a $490-per-month Platinum Turbo plan that includes 1,500 minutes of Internet connection for an effective per-minute cost of $0.33 if you use all the minutes. Additional minutes on this plan are billed at $0.69 per minute. Clearly not cheap, but for anyone who needs the data-transfer power the system offers, it can be a bargain. Billing is to the nearest minute. Since the customer is billed for the entire time the channel is open, the software will terminate the connection whenever data is not being downloaded. Files are cached, allowing their content to be perused at leisure. The tariff provides for a reduced-cost sustaining charge of $39 per month for periods when the boat is not in use.
Another marine broadband firm called TeleSea offers an Internet access service called TeleSea Blue. The base service that can provide data at speeds of 512 Kbps downlink and 128 Kbps uplink using an actively stabilized dish antenna. The company uses transponders on a commercial communications satellite called AMC-6 that hangs over North America and can reportedly provide service over the entire North American landmass and out into the ocean areas along the coasts. According to Forrest Wheat, CEO of Wheat Wireless, which owns TeleSea, the service is available, "way out into the Pacific, all over the Caribbean." In the North Atlantic, Wheat said the TeleSea service was designed to be available as far east as Bermuda, although the company had not yet tested in Bermuda.
Subscribers to the service pay a one-time installation fee of $50,000 for the satellite antenna and other gear. As part of the fee, the company does a full installation and does periodic upgrades as software and hardware improves. In addition to the installation charge, subscribers pay $995 per month for unlimited access to data.
This system is not for smaller boats; it is a big-boat approach for serious Web users. However, the availability of two such broadband systems, tracNet and TeleSea, is an interesting sign that Web access may become more widely available in the future for the medium-sized voyager.
During our investigation of the tracNet system, we looked into another new KVH communication product, eTrac. This system uses the venerable Inmarsat-C packet data system. Inmarsat-C is particularly well suited for use on small vessels and is also installed on most large ships where it is a part of the GMDSS suite. KVH, working in cooperation with the Danish company Thrane & Thrane, recently introduced a non-GMDSS version of the onboard equipment, called Capsat-C. Although using this system for communication may seem painfully slow, with a receive data rate of 600 bps and transmit rates of 300 and 600 bps, it is more than adequate for most email requirements, and it provides a maximum message length of at least 10 Kb. The equipment is the ultimate in simplicity, consisting of a fixed antenna measuring only 5.75 inches high and 6.4 inches in diameter, an interconnection breakout box, and requiring a computer capable of running the Windows operating system. The antenna contains an internal 12-channel GPS receiver that can be used to transmit vessel position information automatically at programmed intervals &mdash once per hour, once every five hours or once per day. Connected to a compatible laptop computer, the system can send and receive email at a cost of about $0.01 per character.
The system allows selection of the number of bits used to identify each character. Eight-bit encoding allows all normal character sets to be used, including messages that include HTML. Seven-bit and five-bit encoding restricts the character set while reducing per-message charges. The cost of sending automatic position reports is less than for normal message traffic since special encoding is used to transmit the information. As with all other Inmarsat-based systems, eTrac must be registered as a mobile earth station (MES). The remainder of the registration process includes identifying the land earth station (LES) designated to handle your data and the data network identity (DNID). Once through that acronym puzzle, things really are quite simple. Power consumption is very low, only 1.8 watts in receive mode and 23 watts when transmitting continuously. Power consumption per day when used for automatic periodic position reporting is 0.078 watts when reporting hourly, 0.025 watts for reports sent every five hours and 0.011 watts for a once-a-day position report. These power levels can be supported easily by a small solar panel charging a 12-volt battery.
The bottom line is that by using today's technology, almost any boat longer than about 25 feet can enjoy communications and entertainment facilities available only to large ships just a few years ago. The growing availability of both new and used Globalstar and Iridium hand-held satellite phones and various service plans can make them an attractive way to explore onboard satellite communication without making a multi-thousand-dollar commitment to a fixed system.
Contributing Editor Chuck Husick is a sailor, pilot and Ocean Navigator seminar instructor. He lives on the west coast of Florida.
For more information on the tracNet testing process, please view this issue's Web Extras
