Subscribe to our newsletter

Electronics

Web Surfing at Sea Page 2

Electronics — February 2003
By Ben Ellison


Web Surfing at Sea
Part 2: Compression, used in many satellite data schemes, is a contentious issue.
   
 

 More of this Feature
• Part 1: Chart Tricks
• Part 2: Chart Tricks
• Electronics Q&A
• TeleSea
• Follow Me
• MiniWEB

 Related Resources
• Electronics Column Index
• Electronics Feature Index

The classic deployment is Geosynchronous Earth Orbiting (GEO), by which a satellite in perfect balance between centrifugal force and gravity appears to sit quite still as it revolves around our globe at the same speed at which we rotate. It can cover a well-defined area, a large one since it is about 23,000 miles high. However, at that distance it takes serious power to get that much data to earth and carefully aimed parabolic antennas to receive TV-, voice-, or Web-size portions of that signal. Afloat that means a sophisticated device that can quickly compensate for changing heading, pitch, and roll. Getting large quantities of data back up is even more difficult, leading to asymmetrical data rates.

Another satellite system architecture is Low Earth Orbiting (LEO), in which the birds whiz by a few hundred miles up, able to transceive enough signal that Globalstar and Iridium voice data can work with small omnidirectional antennas. But it takes a lot of LEOs to cover that much area, and the technology to keep them all alive and linked to their earth stations is complicated and expensive. Even GEOs don't necessarily offer full ocean coverage, as they concentrate their precious power into spot beams aimed at the land masses where most customers are. Inmarsat is the notable exception, formed years ago to serve the marine community.

In short, the satcom variables--coverage, technology, business plan, etc.--are awesome, and I haven't even touched on frequency issues or the scads of companies with intriguing names like Teledesic, SkyBlaster, and WildBlue "about" to offer some irresistible new satellite broadband solution. But let's look at what's actually available for yachtsmen with a high-speed Internet appetite. The discussion thus far will hopefully help to clarify the products offered by the two major players, KVH and Sea Tel, as well as related sidebars.

Last year KVH introduced TracNet, which uses a 400-Kbps Internet downlink available, though down only, from several DBS (Direct Broadcast Satellite) TV GEOs. On shore, the uplink portion of the Web dialog--your keystrokes, for instance--is handled by phone line. KVH did it with cell or Globalstar, putting a server onboard to manage everything. The new TracNet 2.0 focuses on the now less-pricey Globalstar for the uplink and is even using it on the down side when the boat is outside the TV satellite's continent-centered coverage (or someone else onboard wants to watch TV). TracNet 2.0 also boasts compression software that can make Globalstar's normal 9.6 Kbps act like 56 Kbps. Compression, used in many satellite data schemes, is a contentious issue. It really does work, but results are variable according to what sort of data is being squeezed. If regular "optimal" speed rates are sometimes pie in the sky, compressed rates are probably worse. At any rate, TracNet 2.0 equipment starts at about $6,000 but must be accompanied by one of the KVH's various satellite TV antennas, which start at $3,500. Service starts at $.99 per minute and can drop to $.33 with a high volume.

Also debuting last year was Sea Tel's unique all-LEO broadband product, WaveCall MCM 3, featuring three Globalstar modems whose multiple streams are mixed and compressed to feel like speeds to 144 Kbps. The system permits simultaneous phone calls. The hardware is $10,000, and service plans range from $2.75 to $1.10 a minute for fast data. Sea Tel just introduced WaveCall 4003, meant for quite large yachts. It uses high-frequency GEOs and an antenna engineered to fit a 48-inch dome and offers 512/128 Kbps down/up speeds, both expandable, and voice. Coverage is wide, but not global. Hardware is $35,000, and a $1,000-a-month contract includes a gigabyte of data.

KVH's new F77 is similarly geared to big boats but uses Inmarsat's latest Fleet technology, providing global 64-Kbps voice and data like the old B service, but with lower rates and a choice of billing by the minute or by the bit. It's significant that both of these systems allow users to be constantly online, collecting e-mail as it comes in, or surfing at leisure, and paying only for the data downloaded.

The accidental $50,000 phone bill may be history, though there is unfriendly software out there that wants to download stuff when you're not looking. I'll leave it to megayacht skippers and consultants to sort this problem out as well as all the other variables involved in the difficult business of broadband at sea. The technology is amazing, but it's clearly beyond my means at the moment. If I ever make the Galapagos, I'll just have to lay on the beach, Web-less, and watch the GEOs and LEOs glint in the sky.

KVH Phone: (401) 847-3327. www.kvh.com.
Sea Tel Phone: (925) 798-7979. www.seatel.com.

Ben Ellison has been a delivery captain and navigation instructor for nearly 30 years and was recently editor of Reed's Nautical Almanacs.

Next page > Q&A > Page 1, 2, 3, 4, 5, 6

This article originally appeared in the January 2003 issue of Power & Motoryacht magazine.

Related Features