Using Iridium for data

Sending e-mail via my Iridium satellite phone sounded simple enough. I needed to attach the data adaptor ($95) to the bottom of the Iridium phone, attach an RS-232 DB9 cable ($20) and a serial/USB adaptor ($40), and then plug into the USB slot on my laptop. Software from one of the specialized marine e-mail providers would configure the modem and Outlook Express, and I could send and receive e-mails around the world via satellite – even offshore.

The idea sounded wonderful. The e-mail service would strip incoming and outgoing e-mails of all superfluous bits and bytes. E-mails would then be compressed and sent, resulting in a savings of up to nine-tenths of the airtime (at $1-$1.50 per minute) used by a normal e-mail connection to Iridium. In addition, I could download free or inexpensive weather maps and forecasts, and use Iridium for voice calls. I was sold.

I purchased my Iridium 9505A (about $1,500) phone from one of many retailers listed on the Iridium Web site. Vendors tend to specialize; some are aviation oriented, others cater to the needs of land expeditions, and some are marine experts. Some companies sell refurbished phones at a discount. I went for one of the marine companies located near my boat in Florida. I anticipated (correctly) that I might need to return to the vendor for assistance, so I opted not to order the unit through the mail or the Web, though some Internet vendors had attractive prices.

The vendor installed a subscriber identity module (SIM) card in the phone and initialized it. I was assigned an Iridium phone number with an 8816 prefix and a total of 12 digits. The prefix is a special one for the Iridium gateway.

SIM cards are removable and may be replaced by the owner of the phone or stored separately. This would prevent the phone’s unauthorized use, but might slow things up in an emergency. Tiny SIM cards would be easy to misplace. If you are worried about security, you can also password-protect access to calling, but again, this could be a problem if your crew had to call for help when you fell overboard.

Some terrestrial phones can call 8816 numbers directly, and directly dialed incoming calls are free to Iridium phone subscribers. However, charges are usually high ($2.50-$15 per minute) for the caller. Check with your service provider.

Two-stage dialing

One option is to use two-stage dialing. Several satphone service providers offer this service. You call a number in Tempe, Ariz., (480-768-2500), then key in the Iridium number at the prompts. Two-stage dialing reduces charges to the terrestrial customer for whatever long-distance fees apply to a call to Tempe. The Iridium customer then pays for the airtime when the call is connected. With Iridium airtime currently running from $1-$1.50 per minute, the total cost per call is less using two-stage dialing.

When making calls from the Iridium phone to landlines, the full airtime charge applies, but there are no additional long-distance charges. You have to be sure to dial the correct country code. Other Iridium phones can be dialed for half the normal rate.

Airtime can be pre-purchased in lots of 500 minutes or more (good for one year), which drops the current rate to about $1 per minute, based on widely available promotions at press time. Some companies offer monthly plans with various combinations of included minutes and airtime rates. It is worthwhile to compare plans to match your intended usage. We purchased a 500-unit airtime card, thereby avoiding monthly billing issues. The remaining minutes will carry over to the next year if we purchase more airtime before our current 500 units expire.

A new messaging option has recently become available. Short message service (SMS) messages up to 160 characters long may be sent to Iridium phones for free. This is accomplished by visiting a Web service. Your Iridium phone provider should have this option somewhere on its Web site.

Those 160 characters get used up fast, so SMS is best used for a message like, “Call me as soon as possible.�VbCrLf Iridium users can respond with a 160-character message for about half a unit of airtime. Some service providers use the SMS feature as a way to alert Iridium users of incoming e-mails or other useful information.

Final set-up

After bringing the Iridium phone back to the boat, final set up took some time even with several careful reads of the instructions (which were no doubt written by the same folks that write programming instructions for microwave ovens and video recorders). I turned on the phone for the first time and within a few minutes the display was showing that the phone was “registered�VbCrLf and had a strong signal, even down below in the cabin using the standard attached antenna. The Iridium manual insists that clear access to the sky is necessary, but it seems to work reasonably well within the confines of a fiberglass sailboat. It may even work inside some buildings, though hard structures (like masts) do seem to block signals. A better signal can often be achieved by simply wandering around the boat until the signal-strength indicator improves.

Signal strength is indicated by the usual bar graph in the upper left-hand corner of the screen. In general, I’ve found that you can initiate voice calls when you have three or more bars. However, service providers have advised me that a five-bar signal on the phone is mandatory before initiating a data call. Unfortunately, especially on a moving boat, signal strength comes and goes rapidly, meaning you might start dialing with five bars only to have the signal drop to two bars before you’ve placed the call.

It is important to watch signal strength for a few minutes before placing data calls. Wait for a period of signal-strength stability. Once connected to the data network (more about that later), the system seems to be able to handle variations in signal strength better than when initiating the connection.

My first few voice calls to and from my father went smoothly and sounded better than the average mobile telephone connection. The voice connection would work well for emergencies and quick updates. I particularly like the idea of being able to discuss my situation with rescue or medical authorities, if that uncommon situation should ever arise. One could easily carry a satellite phone into a life raft, an advantage over SSB radio.

The phone is fairly water resistant and a variety of waterproof cases are available. I opt to keep mine in a heavy-duty zip-type plastic bag stored inside a protective and padded computer case. An even better option would be to store the unit and accessories inside a waterproof briefcase, such as the popular Pelican line.

Easier install

Voice quality was great, but data is what I was really interested in. Many voyagers opt to receive e-mail via HF SSB or amateur radio and Pactor modems, but I was attracted to Iridium’s supposed reliability and ease of use. Set up time for Iridium is a fraction of what it takes to install an SSB radio, tuner, antenna, ground system and modem. Also, I was greatly drawn by the ability to carry the phone ashore or into the life raft. Unlike HF SSB, there is no need for an external antenna or a special grounding system. The phone’s internal battery provides hours of talk time.

The latest Iridium-capable portable phone is the Motorola 9505A, which is about the same size and form factor as a handheld VHF radio with the addition of a stubby rotating antenna. The antenna should be kept near vertical for best reception. Inexplicably, there is no built-in data connection, but there is a row of contacts on the bottom of the phone protected by a flimsy plastic cover. The accessory data adaptor clamps to the bottom of the phone, providing a RS-232 DB9 serial port, which is compatible with a 10-year-old PC’s port for an external modem, but unlikely to hook up easily to a newer computer that relies on USB ports. To add to the problem, the serial port is male, but has the lugs that are normally on a female serial connector. I cut off the lugs on a female serial cable end with a hack saw and used electrical tape to hold the two parts together – not elegant, but strong and somewhat water resistant.

Iridium offers its own data kit, which includes the required data adaptor for the phone, a serial cable, some software and a stand to keep the phone in the proper orientation. Many users without serial ports on their PCs will still need to purchase some sort of serial-to-computer interface device, as discussed below. E-mail service providers also include software, which seems to be just as good or better than the Iridium data package and just as fast. These e-mail services interface with standard programs like Outlook Express to allow you to compose and read e-mail.

I found the e-mail software provided by service partners to be somewhat awkward to install, requiring some knowledge of PCs beyond point and click. However, your Iridium vendor may have a service to sell and install for you. At this time, there are no Mac-friendly e-mail services for Iridium users, though there are hacks available on the Web that allow Safari (Apple’s Web browser) to interface with Iridium’s Direct Internet service. These hacks do not provide e-mail compression or other speed-enhancing features.

USB to serial solutions

USB connection

The solution to the serial/USB non-interface is either a PC card with a serial connection or a less-expensive serial-to-USB adaptor. A variety of the latter can be found on the market, but they seem to be finicky devices. Unfortunately, I purchased one of the more temperamental models first, a Keyspan 19HS. After burning up several days and quite a few dollars of dropped Iridium connections, and many consultations with the phone vendors and my e-mail service provider, I decided it was time to try another adaptor.

The symptoms of the problem were baffling. The e-mail software seemed to correctly configure everything, and I was soon dialing into the Iridium Direct Internet service. The phone display would tell me that a data call was in progress, but after a few moments, a little dialog box would pop up on the PC telling me that it was authenticating – meanwhile my $1 minutes were burning up. However, before I actually connected to the Internet, and before I could send or receive e-mail, the connection would be cut short and an error message would pop up on the PC.

My Iridium provider diagnosed this as classic serial/USB schizophrenia. A Google search supplied further evidence that others around the world had experienced similar problems that could only be cured by finding the proper adaptor. I picked up further hints via cyberspace that Sealevel was producing a working adaptor, so I ordered one next-day UPS only to experience continued connection problems.

Having blown something close to $150 on equipment that wasn’t doing its job, I finally bit the bullet and purchased a PC card from my Iridium provider. The card had a short cable with a dedicated serial connector on the end. I just plugged it into my PC, attached the serial cable to my Iridium data adaptor and tried a call to Direct Internet. Data connections at last!

I am sure there are many combinations of serial/USB adaptors that will satisfactorily connect PCs to the Iridium data network, but in my case I have found much better reliability using a PC card.

How fast is fast

The whole point of this exercise is to get and send e-mails and other data, and the specialized e-mail services provide interfaces to make this process fast and easy. Everyone wants to know how quickly this works in the real world. Like many things, it depends.

The official speed limit is 2.4 kb with an “effective speed�VbCrLf of up to 10 kb using compression software. In my early trials with the system I have found that I can send about five typical e-mails and download 10 to 15 in about a minute or two, translating to a cost of about $2 of airtime. Of course, your typical e-mails may vary. A large portion of airtime is used initiating the call and logging onto the network and then your e-mail provider, so once you are online it is cost-effective to send or receive as many e-mails as possible. It makes sense to only log in once a week or so to limit the amount of airtime wasted on connection chores.

To further reduce these costs, some services automatically quarantine large e-mails, sending the user a message that there is a big one in jail. You can then download the message using a Web browser when you get to port. The user sets the size at which a message gets quarantined. It is important to train your correspondents to limit message sizes, eliminate attachments and use plain text. Some services translate all HTML messages to plain text, eliminating attachments and images.

Every service provides a Web portal for shore side access to your mailbox. It is a good idea to empty that mailbox frequently when you are ashore in order to limit the quantity of messages you have to pay for later. It is also wise to reply to messages using another e-mail service or address in order to keep your Iridium address as private as possible. This is especially important when contacting businesses or placing orders via e-mail, as virtually every vendor will put you on their junk mail list.

It is possible to request e-mailed versions of weather broadcasts, weather faxes, weather maps and satellite weather products. Ocens offers a particularly broad suite of weather products. WeatherNet has a smorgasbord of weather products that you can request and pay for individually. You must purchase the software ($99) and then you can download “20,000 continuously updated weather products.�VbCrLf Most individual products sell for $0.18 to $2 with the average hovering below a $1. Ocens’ GRIB Explorer ($199) allows you to view and even animate GRIB files available as part of WeatherNet.

If you’re interested in paying nothing for your weather, provides “Internet services for the bandwidth impaired.�VbCrLf The service was developed to provide weather information and other Internet pages to SSB users of Sailmail and Winlink. Iridium users or anyone with access to e-mail can also request these products for free.

You have to request an index of products from an automated e-mail server, and then you simply send another query to be automatically sent the requested forecast or Internet page. Weather forecasts come in compact plain text files. Larger GRIB files are available too, but you’ll need a GRIB viewer program for your PC. If you prefer, you can subscribe to certain products and they will be e-mailed on a regular basis. Even Web pages can be requested, but pages translate to plain text in different ways. The Saildocs site has this disclaimer: “The fancier the page, the worse the results.�VbCrLf

Using Iridium for voice communications is nearly as easy as using a standard mobile telephone, and the results are just as good. Utilizing Iridium for data, particularly e-mail, is a bit more problematic, but is less involved than setting up e-mail via HF SSB or Ham radio. E-mail via satphone burns up between two and three minutes of airtime per week plus one or two bad connections. Even at a cost of around $5 per week, I believe this is a cost-effective way to stay in touch datawise.

By Ocean Navigator