Satellites route e-mail'and spam'through space easily
- By John Breeden II
- Sep 23, 2002
Bulky GSP-1600 handset had separate antennas for wireless or satellite network use.
Henrik G. DeGyor
Navigators of yesteryear relied on the stars when crossing oceans and prairies. These days, they get their data'and voices, too'from a closer source: satellites.
The Globalstar GSP-1600 tri-mode satellite phone I tested looked like a large Qualcomm Inc. phone with two antennas. When the cellular antenna was extended, it functioned like a Qualcomm wireless phone. The second antenna, a black circular affair as long as the phone, tapped into Globalstar's satellite network.
Having tested Globalstar phones before, I knew that cell calls would seem just like those from an ordinary wireless phone. Satellite calls, however, would depend on the testing area. In and around Washington, I had three satellites available.
Because of the phone's three communications channels'Globalstar satellite, Code Division Multiple Access wireless and Advanced Mobile Phone Service'most of the handoffs were so-called soft handoffs.
While I was actively communicating with one satellite, my call would suddenly switch to another with a stronger signal. I could barely notice the change.
That's different from cell handoffs, in which a caller completely leaves one zone before connecting in another. Most dropped calls occur during such hard handoffs.Good old modem
I also tested the Globalstar phone's cellular modem, which plugged into the serial port of a notebook computer. That's about all the setup required. The modem cable did not add any significant weight or bulk.
On a train trip from Washington to Boston, I used the cellular modem and the satellite network to read my e-mail. The rate was slow, sometimes falling below 14.4 Kbps, but it worked fine for e-mail and other low-bandwidth applications. A Globalstar user could download the daily spam from most anywhere in North America.
As the train moved, I noticed that signal strength fluctuated quite a bit, but my connection never dropped. On a separate cell phone I was using, several calls were dropped.
Theoretically the global satellite network could even connect a phone on a fast-moving airplane, although that would be illegal under Federal Aviation Administration regulations.
The Globalstar phone with modem had the same limitations as an ordinary GSP-1600 cell phone'mainly size. Company officials said they are working to reduce its bulk.
Near the end of my testing, the satellite service grew increasingly unreliable. I'm uncertain whether the network was at fault or whether the company was in the process of closing down my test account. In the week before I sent the phone back, it could not connect to any satellite in the Washington area, though cellular service still worked fine.
As more and more users move to satellite communications, the available bandwidth is bound to get overcrowded. In contrast, stars never have too many users.
John Breeden II is a freelance technology writer for GCN.