August 2 , 2001 - Iridium

Whether or not you believe in coincidences, our Mini-M satellite modem failing the day Iridium started its data service seemed bizarre. Protracted tests with our ISP confirmed that our modem was only transmitting garbage, and to get it repaired meant a return to the US manufacturer. As we were on the point of leaving New Zealand, and our visas had expired, this wasn't an option.

Without debating the joys of cruising unencumbered by the modern world, our particular circumstances require us to have e-mail. So what to do? Remembering a recent magazine article recounting the phoenix-like reincarnation of the Iridium satellite service we went on-line for information. Iridium's excellent website provided an impressive amount of information, including downloadable manuals.

We had investigated Iridium three years earlier but there was no data service--it was voice only--so instead we bought a Mini-M terminal. Then a terminal cost $7,500 against $2,500 for Mini-M, plus $1,000 of free calls, so it was no contest. Now the situation had changed--the data service was available as of June 1st 2001, and Iridium handsets were $850 against $3,000 for a replacement Mini-M terminal--so we contacted Auckland-based ROCOM, who had handsets in stock and were awaiting their first data adapter.

Nervous about buying a potentially dead-end product, we ordered. However the new Iridium company bought the old company's assets for a fraction of their value, and say their overheads are 10% of previous. They also signed a $72m, two-year contract with the US military, which should help them through to a sustainable user volume. We hope they are right and have our fingers crossed.

Apart from the price, Iridium has significant advantages over a portable Mini-M terminal, which uses 4 geostationery satellites (i.e. orbiting in parallel with the earth' rotation such that they are always overhead a fixed point on the equator). The bearing and elevation to point the Mini-M aerial is determined from a satellite location chart. Sounds difficult, but is normally easy--at least until the boat swings at anchor, the autopilot heads up or the boat heels--so constant monitoring is required to maintain good signal strength. Also, Mini-M coverage is focused on particular areas--for example, it doesn't exist between Galapagos and French Polynesia.

Iridium changes all that. With 66 low earth-orbiting satellites, coverage is global and, subject to a view of the horizon, 100 percent available. Messages from our handset are bounced between satellites until they go to Earth in Phoenix, Arizona.

Our big box of new toys arrived hand-delivered by ROCOM's director Andrew Wilson, as interested to see how e-mail worked as we were. Included in the package were an Iridium handset, a universal AC charger with adapters for different countries power outlets, a 12v charger and a car aerial. The last we use in place of the normal aerial, keeping the handset dry below with just the aerial poked out through a hatch. Permanently mounted external aerials are available. Also included were a set of pouches to neatly store everything.

The data adapter is an optional accessory and has a cable for connecting to a computer serial port. Also provided is a flimsy cradle, maximizing aerial performance by holding the handset, data adapter and charger vertically. The whole construction resembles a Lunar Lander; far too wobbly for use on a yacht so we dispensed with it.

We turned on the handset, pushed the aerial out of the hatch, were immediately connected, and received a welcoming text message from ROCOM (more of this later). A good start, no more aerial pointing.

We installed the data service software on our computer. Although we had scanned the manuals we had missed a couple of nuances, but after a couple of hours it was up and running. Detailed following of the instructions would have saved a lot of time!

The data service comes in two forms. The handset is used to dial an Internet Service Provider (ISP) directly as with an ordinary modem. Alternatively, an Iridium service, Direct Internet Connection (DIC), is used to connect to an ISP through Iridium's Internet portal and via the internet - this will only work if you have a POP3 e-mail ISP. Using DIC has the advantage that the connection will switch off (called 'spoofing' for some reason) when the connection is idle, and switch back on when data is to be transferred, which along with automatic data compression, reduces connection times.

How did it work in practice? Very well. We have used both direct-dial and DIC to connect to our e-mail ISP, Super-Hub, and to conventional POP3 servers. Super-Hub provides an especially developed e-mail compression routine which sits behind Microsoft's Outlook or Inbox (not Outlook Express) and heavily compresses e-mails to only raw text and minimum addressing. It also manages the connection with concurrent sending and receiving, not one at a time as with Outlook Express (see screenshot below). If using direct-dial, having an ISP based in Phoenix would give best results, but Super-Hub has a US access number that works well. For example we sent 10 e-mails, most being several small paragraphs but one a short article, and received back 4. These compressed to 13k out and 4k in, the whole transaction being completed in a 1m 12s call at a cost of $2US. Super-Hub's transmission rate was running at over 450 characters per second, suggesting a data rate of double the 2400bps (about 250 characters per second) advertised Iridium data rate, probably due to its ability to concurrently send and receive. It is not always as efficient, sometimes glitches slow it down, but far less in number and overall much faster than our Mini-M, which normally ran between 50 to 90 characters per second.

Using DIC and Outlook Express to access e-mail through a normal ISP also works well, with Iridium's compression routine working at 20:1, we downloaded 85k of e-mails in about 6 minutes.

Internet surfing is possible, although expensive. Turning off browser images improves speed as only text is transferred, but it is still slow. We previously imagined downloading weather maps, but these are images so browser images go back on and we get the lot. Directly requesting the page required is better than browsing to it.

Overall, Iridium is working out cheaper and easier to use than Mini-M. Call charges are about the same at $1.50 a minute, but Iridium charges for the first minute and then at 20sec intervals, so some time is always wasted. This is annoying, obviously Iridium could charge to a second, it seems a sneaky way of reducing their advertised charge to $1.50. Our e-mail calls average 1m 30s, on that basis Iridium's charge should be $1.67 per minute. Not a huge difference, but significant on a monthly bill.

At $1.50 a minute, it is competitive against long-distance calls from places such as Tonga and Tahiti, and a lot more convenient than going ashore and finding or waiting for a telephone. Calling us is expensive--for example, from New Zealand, US$7.50 a minute. However Iridium provide a free 120-character messaging service, so if we need to be contacted, a text message can be sent to the handset through Iridium's website either on-line or via e-mail.

Below: Screenshot of email window.