capsule review

AirPort Extreme Antennas

At a Glance
  • Dr. Bott ExtendAir Omni

  • Dr. Bott ExtendAir Direct

Apple's AirPort Base Stations can liberate you from the shackles of Ethernet cable, but sadly, their range often doesn't extend as far as most people can throw a stone. In my average wood-frame house, my AirPort Extreme reception drops to almost nil the second I go upstairs and turn the corner -- no more than 25 feet from where the snazzy white Base Station sits blinking cheerfully in my office. This puts my bedroom out of its reach, and isn't surfing the Web from the comfort of one's bed the whole point of having AirPort?

Meet the Dr. Bott ExtendAir antennas, which plug right in to the AirPort Extreme's antenna port (on the $249 model only).

Dr. Bott claims that the ExtendAir Omni instantly triples the AirPort Extreme's coverage area (in all directions), and that the ExtendAir Direct extends the range from 50 to 500 feet in one direction. While the reality is not quite that rosy, I found that both ExtendAirs do indeed greatly improve AirPort range and speed. And they couldn't be better looking, with sleek white cases and curvy bodies that match Apple's design in every way.

How Much Range Is Enough?

The ExtendAir Omni ($100) is a vertically oriented antenna that provides coverage 360 degrees around the antenna. In technical terms, it provides a 3.5 dBi gain in antenna power to the AirPort Extreme's 15.0 dBm of power. To serious networking techies, that might not sound like much, but combined with the omnidirectional coverage, that gain yields a substantial increase in range and throughput.

By contrast, the Extend-Air Direct ($150) adds even more antenna power (6.5 dBi worth), but it focuses its coverage in a 70-degree beam. It's designed for long corridors and large open rooms such as warehouses and auditoriums. It, too, betters AirPort coverage.

As any AirPort user knows, performance claims are always optimistic, and real-world results are much lower. With no added antenna, the AirPort Extreme promises a 50-foot range at 54 Mbps, and a 150-foot range at 11 Mbps. The Omni purports to extend the 150-foot range to 250 feet, for an overall threefold increase in coverage area, or 67 percent in any given direction. The Direct promises to extend the range to 500 feet, but only in one direction.

So just how much do these antennas actually improve your range? In my house, the Direct gave me more than double the range of the AirPort Extreme in one direction, and the Omni increased range by about 50 percent in all directions. That was only 20 to 50 additional feet of coverage, but the antennas made the difference between two-room coverage and coverage of my entire 1,450-square-foot house, which was all I needed. Of course, your results may vary.

Speed Matters

Wireless throughput drops drastically as signal strength decreases, so the improved reception provided by antennas can increase throughput. (The number of little black curves in the AirPort menu-bar icon roughly indicates signal strength.) The shareware utility MacStumbler more accurately measures reception quality by sniffing out available wireless networks and telling you their signal strength. In my tests, I used MacStumbler as a gauge of relative signal strength, which nearly doubled at all ranges with the Direct antenna and increased by a little less with the Omni. (On MacStumbler's scale, a weak signal is below 40 and a strong signal is 70 or higher. The highest MacStumbler rating I've seen -- for a signal measured right next to a Base Station -- was in the low 90s.) For example, without one of the antennas, signal strength 25 feet from the Base Station dropped to the 20s in my house. With an antenna, that number rose to around 40, an acceptable connection. I also noticed a greater effect on throughput when I used the 15-inch PowerBook G4, which has notoriously worse built-in AirPort reception than the 12- and 17-inch PowerBooks and the iBooks.

Macworld's Buying Advice

If you need better AirPort Extreme range in a limited area, one of the Dr. Bott ExtendAir external antennas may be the perfect solution. Each is a lot less expensive than a second AirPort Extreme Base Station but more expensive than many third-party base stations that let you extend a network's range by using additional base stations. The Omni is the best choice for most homes. The Direct is a better choice if you live in a narrow home or flat with a long central hallway. I'm hooked on the Omni, which finally fulfills AirPort's promise, extending my Base Station's range to cover my entire house -- even my bedroom.

At a Glance
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