Iridium claims total coverage of the earth. We’ve heard from users in Tierra del Fuego at the bottom of South America, and we know it works in Alaska.

Above is a coverage map from the Globalstar website. Orange is called primary reception, yellow “extended” and blue “fringe.” What we know from our own experience last summer is that we had intermittent connection service in Southeast Alaska and offshore in the Pacific Northwest, where the map shows “primary” reception.

When we decided to activate one of our sat phones in Alaska last summer we checked with the local fishermen. Globalstar has a poor reputation so we were going to use Iridium. However, we were informed that Globalstar has added a new ground station and that they would now have good coverage, so we signed up with them. The reality is that the Globalstar system performed so poorly for us in Alaska that we stopped using it. We heard later that they were having intermittent problems affecting their system, and this may have contributed to our lack of performance.

Bottom line, be sure and talk with folks who have real world experience with these systems where you are planning to go before deciding.

For data and phone service with Globalstar if you are outside of your primary coverage area and your signal goes through a different country’s ground station, you pay roaming charges, which are substantially higher than the domestic plan per minute costs. With Iridium, the per minute charges are the same anywhere the phone is used.

Both of these phones provide data transmission and reception, albeit at slow rates. The Iridium is good for 2400 baud, the Globalstar three to three and a half times this rate.

Both systems have a variety of payment plans. Iridium seems to settle a little above one US Dollar per minute. Globalstar offers plans down to a quarter of this – but again, make sure you know the service works reliably in the area where you are planning to use it.

We signed up with UUPlus ( http://www.uuplus.com ), an e-mail compression service, for our trip back from New Zealand. They have proprietary software which is easy to use, and have great technical support. The SetSail articles we sent from Wind Horse were all done with Iridium and UUPlus. An average report, with four or five photos, would take five to six minutes to send (photos were optimized for the web in Photoshop).

We asked Jeremy Bonnett, one of the principles of UUPlus, for his opinion on which system would work best for our upcoming trip to Mexico. His feeling is that at the present time Iridium is still the best. Their mix of reliable coverage, constant cost, and slower speed is better for our needs than Iridium with its roaming charges and requirement to use the Mexican land lines once a signal has been received at a ground station.

There is a new option coming soon which may be of real interest. This is called BGAN, from Inmarsat. This is a high-speed cable modem-like service. Service right now is over the North Atlantic and Indian Ocean. The Pacific is due to come on stream in another year.

At present they have just a land portable transceiver, which is aimed at the satellite and left stationary in the aimed position. This won’t work on a boat unless tied to a dock.

BGAN offers several payment programs. The one which looks most interesting to us is a $5 per megabyte package, without any monthly fees. The problem is that there is no marine system yet available, and when one does come on the scene it is likely to be very costly. However, they mentioned a land system was being tested which would track from a moving vehicle. When we heard this our interest really perked up.

“Would this work with the vehicle turning a circle?” we asked. With a reply in the affirmative we realized that a FollowMeTV type of system might work (we are using FollowMeTV’s single axis tracker on Wind Horse for our satellite TV system – it is basketball season now and we need our Arizona Wildcat coverage). If their system works for satellite TV, why not BGAN? We’ve got the two companies talking and we’ll report back on what we find. You may have read our previous two articles about this, posted on Dec. 3 and Dec. 19, 2006.

Once Inmarsat has BGAN coverage for the Pacific, if they can combine their dish with FollowMeTV, this would be the ideal situation.

For now, we will use Iridium.