Ocean Navigator: Newsletter #3


The Holy Grail of Marine Communications


A client recently phoned up to ask a simple question. "What can I get that will offer high-speed Internet connectivity at sea, with a reasonably small antenna, with global coverage without spending a lot of money?" My response was simple, "My friend, you're looking for the Holy Grail of marine communications."

Actually the situation is improving quickly. With KVH's TracNet offering North American coverage, and SeaTel's Globalstar based WaveCall coming on line, high speed options are beginning to be available. However, for global coverage the exciting news will be the launching of Inmarsat's F service. The service will offer 64 Kbps (multiplexable into 128 Kbps). Coverage will vary depending on antenna type but will initially cover the same area as Inmarsat's MiniM service (most of the northern oceans and some of the southern oceans). Eventually there will be three flavors of the F service with different antenna sizes and coverage areas. Early reports suggest the following specs:

- small antenna (30-35 cm diameter) would cover the MiniM regions at 16 to 32 Kbps
- medium antenna (45-50 cm diameter) would cover the same regions at 64 Kbps
- large antenna (70-85 cm diameter) would cover global regions (except the polar areas) at 65 Kbps

Service is scheduled to launch sometime soon for one flavor, with the other two to follow over the course of the next year. The big question in everyone's mind is still unanswered: How much will it cost? Early reports place the equipments costs in the ballpark of $25,000.

One very interesting feature is that you will have the option of being billed by the packet and not by the minute. This means you'll be charged for the *amount* of data you send, rather than the *time* it takes for you to send it. While it seems like a minor difference, it's really a revolution in the world of remote networking and allows for a bevy of new onboard applications. The vessel can stay "connected" 24 hours a day! Feel free to write in with ideas about how you think you'd be able to use this service. I'll share some of my own ideas along with some more details about available products in a future issue.

- Dan Piltch
dpiltch@MarineComputer.com

READER FEEDBACK

RE:DSC VHF --> Dave Bender writes in that

You mentioned the VHF eavesdropping problem, but failed to mention that there will be some station to station encryption features coming up. For one, contact Maritel. They are, or are going to be, offering a speech privacy capability."

Mr. Bender is 100% correct. The fishing market in particular has been very keen on this speech privacy feature as they'll be able to share information about lucrative areas without broadcasting it across the public airwaves for all to hear. In addition, Maritel will also offer data connectivity, touch-tone dialing, and position reporting. They're new network in the Gulf of Mexico is just about complete, and they're working on expansion as we speak. Unfortunately, for us up here in Maine we've been left out of Maritel's VHF revolution as we're out of their coverage limits and that's not likely to change anytime too soon.

RE: Bandwidth and bps --> Bill Finkelstein writes

Dan - your math is a bit off....

2400 bits per second / 8 bits per byte = 300 Bytes per Second.

It's worse than that, however, as most dialup equivalent protocols are "asynchronous" and add a start and stop bit to each byte - so a byte is usually 10 bits long. That takes us down to a measly 240 bytes per second.

Bottom line - I'm training a flock of albatross to transport CD-RW media - they have a greater range than carrier pigeons ;-}

Wow - an embarrassing error! Perhaps the flock of albatross isn't such a bad idea after all. Thanks for pointing this out.

- Dan Piltch
dpiltch@MarineComputer.com


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