I would like to address a somewhat misleading analysis of the relative costs of satellite communications systems that appeared in your otherwise insightful coverage of marine electronics in the 2004 issue of Ocean Voyager (Offshore communications update). The author makes a straightforward but simplistic comparison of the raw costs per byte transmitted between a packet data system (SkyMate) and a connection-based system (Globalstar satellite phone). Such a basis for comparison overlooks two important aspects of SkyMate’s packet-based system that make it a cost-effective choice for many mariners.
First, SkyMate transmits text email files much more efficiently than connection-based systems. This is because satellite phone airtime is billed in one-minute minimum increments, so for a message of less than 1,000 bytes, 98 percent of that one minute of airtime is unused. With SkyMate, the user is only charged for the amount of data actually transmitted. A user sending five separate emails per day over a Globalstar phone would use about 150 minutes of airtime per month, which in the Caribbean would cost more than $120. The same usage profile using SkyMate would cost less than $70.
Second, packet data systems are always on, meaning that SkyMate messages are automatically delivered within minutes to the vessel anywhere in the coverage area. By contrast, with connection-based phone systems, the user must initiate a mailbox check, which uses airtime regardless of whether any messages are retrieved.
So for a user regularly sending and receiving text emails, a packet data system such as SkyMate offers one of the lowest-cost solutions available.
John Tandler is CEO of SkyMate Inc.