[Paul Elliott]

I was assuming that you would be starting from scratch, and so had to buy the SSB and Pactor modem (neither of these is cheap). How long it takes to make up the (usually) higher initial cost of the SSB gear will depend entirely on the way you use it. For casual or part-time users, the optimum solution may not be so obvious.

Obviously there are ways to save money on the SSB installation (ham gear and Winlink, mainly), but the Pactor-3 modem is fairly non-negotiable.

I've used both SSB and Iridium for email during my three trips from San Francisco to Hawaii and back (SSB-only during the first trip), and I stand by my observation that the Iridium gives me roughly 2x the data speed, or better. In 2008, I downloaded about 100 to 200 kBytes a day of grib and compressed WFAX charts, plus a small amount of regular text email. I am reasonably experienced in time/frequency selection for propagation, and I doubt that anyone who has used both systems would disagree that Iridium is significantly faster and more reliable. I do welcome other opinions (anyone?) Note that with my large data transfers, Iridium was definitely the higher-cost option. I'm pretty sure that Sailmail would not have allowed me to receive this much daily data. I could have done it with Winlink, but I wouldn't have made many friends in the process.

I got my data speed numbers from the Pactor and Iridium specs -- these are raw, uncompressed speeds. Built-in compression is available with either service and will provide roughly the same increase in throughput.

Don't get me wrong, I like SSB and wouldn't want to sail without it. If you do a lot of communicating, then SSB will probably be the long-run cheaper solution. I do suggest that anyone making this decision should really look at their usage plans and crunch the numbers. Also, sometimes factors other than the cost-per-kilobyte will be the deciding ones.