MacSailing.net

Hello fellow Mac users!
We are about two years away from setting sail for a circumnavigation and will be seriously looking at the Iridium sat phones.

On average, how long does it take, in minutes, to receive MacWX data? How much air time is needed on each call with the sat phones to receive/send email and other data? I understand the baud rate is unbelievably slow! Any info will help...thanks.

Matt

a 3 day wind grib file consisting of 12 forecasts (0-72 hours) for a region the size of the caribbean sea takes about 1 minute of iridium air time when using a direct connect via XGate using MacWx.

--luis

Luis Soltero, Ph.D., MCS
Director of Software Development, CTO
Global Marine Networks, LLC
StarPilot, LLC
Tel: 865-379-8723
Fax: 865-681-5017
E-Mail: lsoltero@globalmarinenet.net
Web: http://www.globalmarinenet.net
Web: http://www.starpilotllc.com

The raw rate of iridium is 15Kbytes per minute. Mor e importantly the latency in the link is between 1-3 seconds. That means that it takes 1-3 seconds to get back a response from a server on the internet.

When using standard internet programs such as e-mail and web browsing the link is "unbelievably" slow as you state above.

However, when using iridium aware compression software you can send/receive a lot of data efficiently. Using XGate you can send/receive approximately 10 2-10Kbyte files in about one minute. The actual time will depend on the compressibility of the data.

So... the system is quite usable when using XGate and MacWX to doing e-mail and weather.

--luis