What are 3G Modems? Practically, speaking, they allow you to get broadband internet access anywhere you can get a cell-phone signal! This, of course, is virtually anywhere on land these days and even out to sea about 15 miles or so (and further with special antennas). For the purposes of this article, we refer to "3G" in the generic to refer to this type of technology, even though 4G & higher speeds are now becoming available. OK, it doesn't let you update your webpage from the middle of the Atlantic Ocean, but it's still pretty cool. How often are you in the middle of an ocean? Historically, we're on passage about 7% of the days we're on board. We generally have a cell signal the other 93% of the time.
GSM is the cell-phone technology that's currently used all over the world. Most countries have a GSM network, even remote ones like Afghan Wireless, Nepal Telecom, Celcom (Malaysia), AIS (Thailand) & Telkom Kenya. It's not as popular in the USA but it's growing even there (although the US uses slightly different frequencies for its version of GSM, so a GSM phone or modem from the US may not work in other countries unless it's a special tri- or quad-band unit). 3G is a technology that piggy-backs on the GSM cell signals, providing broadband internet access wherever cell signals are available. Many GSM phones these days have 3G modems built into them, and many allow "tethering" so your computer can get internet access using the phone's data signal.
We first heard of this technology when we were in Brisbane in 2006. Summer in Brisbane is a time of intense thunderstorms, which sailboats don't like at all. Even a nearby lightning strike can destroy many of the sensitive electronics that we carry on board (we lost over $4,000 from a near miss). But the Brisbane airport radar can see these thunderstorms and publishes graphics of them on the internet every minute or so. They'll even show their tracks over the last several minutes, so us cruisers can see if the storms are headed towards us or away. Pretty cool.
But we didn't actually buy a 3G modem until we got to South Africa, paying R1,700 (about $240) for a unit that (we later found) was locked to the Vodacom system. Still, Vodacom and its affiliates cover much of the world. And prices now (late 2011) are only about $30 for an unlocked 3G modem here in Malaysia (and even better if you can catch a promotion).
Connect time is expensive in South Africa, so we had to pay an additional $45 for 2 gigabytes (GB) of data, which lasted us about 2 months if we were careful (but now connect time is much cheaper). In Malaysia, Celcom (which is affiliated with Vodacom) charges about $6/week for 2GB of data, and in the Seychelles, the service is provided for free (or perhaps they hadn't worked out a way to charge for it yet).
Physically, a 3G modem looks a bit like an external WiFi unit - about the size of 1-2 fingers, with a USB tail to plug into the computer. Most units have a light that changes color to indicate your connection speed. To the computer, most units look like a flash-memory ("nerd") stick, and most carry all their software in that flash memory, requiring no additional installation software and providing a complicated but plug-&-play software installation.
Even in Africa, our modem provided us with excellent service. We could be in a rest-camp in Kruger Park, outside our primitive safari-tent, and still be online, while the hyena on the other side of the fence contemplated us, wondering what we'd taste like. Friends of ours were sailing down the coast of South Africa in thick fog, wanting to come into Knysna but afraid to approach the coast and the narrow "Knysna Heads" entrance in the fog. But they were only 5 miles offshore and they had a cell signal, so they checked into http://www.TheHeads.co.za. That site has 2 webcams pointed at the Knysna entrance. No fog, and no swells! So our friends turned towards shore, soon sailed out of the fog, and made a successful landfall at Knysna.
GSM works on 2 frequencies, one usually close to 2 GHz and the other about half that. Like any other radio, a 3G modem will work better if it has a reasonably unobstructed view of a cell tower, and if the antennas are oriented in the same direction. We tend to hang ours up with a string to a hatch or something. Cruisers with metal boats may want to invest in a USB extension cord so they can hang their 3G modem outside their boat, where the metal hull won't obstruct the signal.
For cruisers in Thailand, Thailand is now (2012) rolling out 3G in selected areas, but we found that our Malaysian modem would only get the old EDGE (2.5G) speeds. We needed a new modem to get the new 3G speeds. For about $30/month you could get a plan for more or less unlimited data.
For cruisers in South Africa (and some other countries) there are some tricks to getting the most out of your 3G modem. First, you don't want to use normal airtime for your data - you'll go through it in no time at all. Instead, convert all of the airtime on your modem into "data‑bundles". Since the Vodacom system is designed to start using airtime as soon as you run out of data‑bundles, you generally don't want to have any normal airtime on your modem, just data‑bundles. When we were there in 2008 and 2009, data‑bundles cost R189, R289, or R389 ($27, $41, & $55) for 500MB, 1GB, or 2GB respectively. Obviously, buying 2GB is the best deal, but it only lasted until the end of the next month, so you had to gauge how much you'd use. Unfortunately, you can't buy airtime in those amounts! So the trick is to buy somewhat more than that amount of airtime, put it on your normal cell‑phone, and then transfer over the exact amount you need to your modem by dialing *111# (send) and following the prompts for airtime transfer. The call is free, but remember to hit your "Select" button before typing the number of your response, or you'll have to start all over again.
Then you'll have to remove the SIM from your phone and put in your modem's SIM. You should get a message that you've been topped up by the amount that you just transferred. Then dial *111# (send) again to convert your transferred airtime into data‑bundles right away. When you're finished, including both confirmation steps, remove your data SIM, put it back in your modem, and replace your phone's normal SIM. You'll have to repeat this whole procedure every month or 2 when your data-bundles run out. Strangely enough, the software did not allow us to add more data‑bundles until all of our existing data‑bundles had expired or been used up. This means that you have to be in the middle of a data download and have it fail before you can top up, a truly stupid way to work things. But as they say, TIA (This Is Africa...)
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