High speed Web surfing at sea?Jan 1, 2003
From Ocean Navigator #119 January/February 2002
For voyaging sailors, Internet access used to be largely limited to email, or to Web access using fairly slow satellite links. Now KVH Industries is introducing a high-bandwidth solution for viewing web pages that is reportedly capable of 400,000 kbps on the downlink side. The TracNet system is based on KVH's TracVision satellite TV antenna and a TracNet server box.
For homeowners, there are several companies offering Internet access via geosynchronous satellite the same type of satellite used to broadcast satellite TV services like DirectTV. KVH is now the exclusive reseller of a high-speed satellite Internet service called DirecPC for mobile users. DirecPC uses the digital video broadcast (DVB) satellite owned by Bell ExpressVu, a telecommunications company based in Canada. In addition to signing up for the mobile DirecPC, voyagers will also need a KVH TracNet mobile Internet server onboard and a wireless 802.11bPCI card for their computers. With this gear in place, KVH claims voyagers will have access to the Internet at the impressive data rate of 400 kbps seven times faster that the 56 kbps modem connection than many mariners use at home. And this level of throughput will be available not just at the dock, but up to 100 miles off U.S. coasts. The idea of surfing the Web while offshore in a wide variety of sea states (the KVH TracVision antenna is actively stabilized and can lock onto a satellite even with a substantial sea running) could have far-reaching implications for the real-time dissemination of weather, navigation and charting data to mariners.
One of the features of any broadband is its downlink/uplink symmetry is the data rate the same on both the downlink and uplink sides of the system? KVH's mobile DirecPC system is asymmetrical; the downlink from the satellite is at 400 kbps, while the\uplink, or return link, can take advantage of a variety of communications approaches, depending on which ones are available.
When you use your computer to access the Web, for example, the return link is for sending the request for a web page, while the downlink is for downloading the html file that allows your computer to draw the web page on your computer screen.
The KVH system looks for the lowest-cost approach for sending the return link data. For example, if you are at the dock, and the marina at which you're staying has telephone hook-ups, you can plug your TracNet into a regular phone line for a 56 kbps return link speed. Using this setup would cost you 19¢ a minute. If you are underway but within cell-phone range, the TracNet system defaults to a cellular-phone link at a data rate of 14.4 kbps and a per-minute charge of 79¢. Outside cell-phone range, the TracNet unit will switch to a Globalstar satellite link at a return data rate of 9.6 kbps and a cost of 79¢ a minute. (In all of these cases, you would still use your TracVision satellite antenna for the downlink side of the system). If you are more than 100 miles offshore, and thus outside of the footprint of the satellite, the TracNet system defaults to a symmetrical Globalstar link at 9.6 kbps for downlink and uplink. This data rate is no longer particularly effective for receiving web pages, but is adequate for gathering short, text-only email.
With 802.11b wireless capability included, the KVH TracNet server is set up for wireless networking. In order for the computer or computers on your boat to use this wireless networking feature, of course, you will need to add an 802.11b wireless network interface card to an expansion slot of your computer. For those users who wish to use a wired Ethernet network, the TracNet server is also set up for 10/100 base T networking. KVH has set the price of the TracNet server at $5,995.
In order to use the TracNet system for Internet access, you also need a TracVision satellite antenna. These units range from $3,500 to $9,000, depending on features. KVH plans to officially introduce the TracNet product at the Miami Boat Show in February 2002, and units will be available for purchase at the same time.
Meanwhile, Sea Tel, another firm that offers satellite television antennas, has recently announced a product that takes a different approach to Internet access at sea. Rather than using a DVB satellite, Sea Tel has designed a system called WaveCall MCM3 (which stands for multi-channel modem) that uses low earth-orbit Globalstar satellites. The Sea Tel MCM3 product uses three modems running in parallel. The data from the user's computer is split into three streams, and each stream is run through one of the modems. The data streams are carried by Globalstar satellites, which can handle data at a rate of 9.6 kbps. The result, according to Sea Tel, will be an effective throughput of 28.8 kbps. Software compression is used to further enhance the effective data rate. According to Peter Whyte, president of the WaveCall subsidiary of Sea Tel, the WaveCall MCM3 can achieve landline modem equivalents of 144 kbps.
The antenna for this system is contained within a 20-inch dome that is mounted abovedecks. Unlike the KVH system, which uses an actively stabilized antenna to compensate for the boat's pitch and roll as it sends signals to a geosynchronous satellite 23,000 miles away, the Sea Tel antenna has no moving parts. There is no need for active stabilization since the satellites are in low orbit, roughly 500 miles high. Belowdecks the WaveCall MCM3 will use a single interface with a nine-pin serial port for connecting a computer and an RJ-11 telephone jack for connecting a single phone or a PBX system. One interesting feature that Sea Tel is claiming for the WaveCall MCM3 will be the ability to simultaneously handle voice and data. As for where you can use this system, many ocean areas of the world have Globalstar coverage, including, for example, the northern half of the North Atlantic.
Sea Tel has announced that the WaveCall MCM3 hardware and service will also be officially unveiled at the Miami Boat Show in February. No pricing has yet been set for the system.
Iridium users can send and receive email and get some basic Web access using the data capabilities of the Iridium system. For users of Iridium's direct-Internet data services, data rates are 10 kbps. While Iridium service is slower than other satellite services, it does have the advantage of worldwide availability, unlike Globalstar and DirecPC, which offer only regional coverage. Because Iridium uses a per-minute fee schedule, with charges in the $1.50 a minute range, users can take advantage of Iridium's Smart Connect feature that allows the user to maintain an always-on mode, without running up continuous airtime charges.
All three of these systems represent the arrival of offshore Internet access, even though they are limited by coverage in the KVH case and by low data rates in the Sea Tel and Iridium cases. The upside is that when voyagers routinely have direct access to the Web when at sea, the wealth of information they'll have available could significantly improve their ability to perform a variety of tasks, like keeping track of weather; doing weather routing; gathering and using electronic charts; communicating with friends, family, parts and equipment suppliers onshore; and much more.
Imagine accessing a NOAA website and gathering the latest satellite images, weather charts, Gulf Stream forecasts, GRIB files, etc. Or purchasing and downloading electronic charts as you need them (but always having plenty of paper charts for backup use, of course).
There is, no doubt, an astounding number of possible Web uses that no one has yet thought of that will appear once voyagers begin regularly using the Web from the ocean.Edit Module