[Paul Elliott]

Note that the initial setup costs (purchasing the equipment and installing it) for the SSB/Sailmail system will probably be more expensive than the Iridium satphone system. The annual subscription costs will be similar (unless you can use the free Ham radio Winlink instead of Sailmail). The airtime cost will be free for Sailmail or Winlink, and about $1.25 (US) per minute with Iridium. The basic Iridium data rate is 2.4 kBits/sec. The SSB Sailmail the rate can be as fast as 2.7 kBits/sec, but can be as slow as 77 Bits/sec. In my experience the actual throughput of the Iridium system is perhaps double that of SSB.

So, which one is ultimately less expensive will depend on how you use it. Both SSB and Iridium have their advantages and disadvantages, but you may find that the total cost is fairly similar.