By Brien M. Posey
Proxim’s Skyline 802.11b USB Adapter for Desktops is designed to bring wireless networking to PCs with no open PCMCIA or PCI slots. The unit attaches to the PCs USB port and functions identically to any other wireless NIC.
Basic Features
The Proxim Skyline 11Mbps Wireless USB adapter is nothing more than a wireless NIC that attaches to your computer’s USB port via a supplied USB cable. Its only special feature is that it boasts Macintosh OS 9 compatibility. One thing that I did notice about this NIC though was that the box claims that the unit only has a range of 150 feet. While 150 feet is adequate for many environments, it is far shorter than that offered by some newer wireless NICs coming out, which have ranges of close to a mile.
One of the things that I noticed about the unit was that, on one of my test PCs, the USB adapter kept falling off of the back of the PC because of the vibrations caused by the PC’s six internal fans. Granted, most PCs don’t have that many fans, but even so, I would have liked to have seen some Velcro included with the NIC to help it to stay put.
Setup/installation
Installing the Proxim USB wireless NIC is easy. The process begins by attaching the unit to the PC’s USB port via the supplied USB cable. When you do, Windows will inform you that it has detected new hardware. On the two systems I used for testing, Windows asked me if I wanted to install the drivers automatically or manually. However, upon inserting the CD, installation began automatically, without me ever having to click a button. Windows does warn you that the driver is unsigned and asks you if you want to abort the process or continue the installation.
After continuing past the driver warning, Windows begins copying all of the necessary files. The file copy process is very brief, lasting only about 15 seconds or so on my 2.0GHz test machine.
After the file copy completes, Windows recognizes the Proxim unit as a NIC within the machine. Setup from here is basically the same as for any other NIC. You must configure an IP address (assuming that you’re not using DHCP), and you must set the USB NIC’s SSID and channel. The process for doing so was identical to that of other brands of wireless NICs that I have installed. The process functioned flawlessly, and I didn’t run into anything unexpected.
Performance
I used the free Qcheck utility from NetIQ to measure the Proxim USB wireless NIC’s throughput. I tested the unit under a variety of conditions and on two different PCs. For each test, I performed the test five or six different times and then used an approximate average throughput for the values that I’m using.
I began my performance testing by attaching the unit to an 800 MHz Pentium III Sony laptop with 256 MB of RAM. I began the tests by measuring the throughput between the laptop and a 3Com AirConnect wireless access point from a distance of about ten feet. At this distance, my average throughput was about 4.4Mbps, with the average throughput dropping to about 4.2Mbps after enabling 128-bit WEP.
Next, I took the laptop to a room that was at the opposite end of the building as the wireless access point, but on the same floor, about 60 feet away. Here the unit sustained an average throughput of about 4.2Mbps With WEP enabled, about 3.9Mbps.
Next I went to a room directly beneath the access point, probably 20 feet away but were separated by the floor and whatever duct work runs through it. From this location, the average throughput was roughly 4.2Mbps. This time when I enabled WEP, performance remained basically unchanged.
Now 75 feet away to a location that has been a tough place to get a signal in the past: the average throughput was 3.1Mbps. Upon enabling WEP, it dropped dramatically to about 1.2Mbps.
Finally, outdoors about 150 feet from the wireless access point. Although no buildings stood between the access point and the laptop during this test, there were several trees. From this range, the average throughput was 4.0Mbps, down to 3.6Mbps with WEP on.
I was curious how the wireless NIC would perform in Ad-Hoc mode. To test, I used a Proxim PCMCIA wireless NIC that I had previously reviewed. Because of problems getting my other PCMCIA NIC working with my Windows NT-based Toshiba Pentium lapto, I attached the Proxim USB NIC to a desktop PC and used a Proxim PC Card NIC in my Sony laptop. I configured each NIC to run in Ad-Hoc mode and measured the throughput between the two units using the same locations as before. When the two PCs were in the same room and about 10 feet apart, the average throughput between them was about 4.7Mbps. Performance went as low as 3.6Mbps indoors in the farthest room, and down to 1Mbps outside.
Summary
Although I found no serious problems with the Proxim Wireless USB NIC, its performance was noticeably slower and had a more limited range than some of the other NICs that I have tested. If you need great distance, look elsewhere.
Model Number: PN474 ($149.00)
Pros: No external power supply required; Macintosh OS9 compatible; easy to configure.
Cons: Limited range; slow performance; unit tends to vibrate off of the top of the PC.
Reprinted from 80211-planet.com.
