(Microwave ovens and many cordless phones can "pollute" WiFi's 2.4GHz frequency, which could also explain some of the fluctuations.)

The two newer technologies, 802.11a and 802.11g, advertise a top speed of 54Mbps but require different trade-offs. The 802.11a technology employs the less-crowded 5.4GHz radio frequency to reduce the odds of interference but doesn't work with other WiFi gear (the D-Link "a" access point got around this incompatibility by adding a separate "b" transmitter). The 802.11g technology uses the same frequency as 802.11b and thus can talk to "b" hardware.

Both new arrivals command a premium over regular WiFi hardware, but "a" costs about twice as much, while "g" tends to cost 50 percent more. The novelty of 802.11g also means that "g" units from different vendors may not cooperate or may need firmware upgrades after the standard is finalized.

The speed improvements both technologies promise are real. In the same room, the 40MB test file zipped across in 23.9 seconds under "a" (13.6 Mbps) and 26.6 seconds under "g" (12 Mbps). Two rooms away, 802.11a ran at 10.4Mbps, but 802.11g had slowed to 6.4Mbps. In the den, where the "b" receivers reached their limit, both "a" and "g" hardware sustained a 4Mbps connection.

If speed alone is a priority, then consider that 802.11a hardware consistently performed about a third better than 802.11g in these tests.

Useful 802.11g connectivity ended about 67 feet, one interior and one exterior wall away, while the "a" network reached about five feet farther. This result confounded our expectations; most reports have found that 802.11a's range falls short of 802.11g's. Interference from other 2.4GHz devices in this and neighboring houses might explain that discrepancy.

The bottom line? The 802.11b technology does fine for most local networking, as long as huge file transfers don't happen often. After all, its real-world speed still outpaces a broadband connection. The 802.11a technology works quite well, but once the 802.11g standard is settled later this year, this technology's better compatibility will make it the obvious choice.

In the meantime, almost anybody can improve the performance of a WiFi network just by rethinking the placement of its access point. Our initial test installation had an access point parked next to the DSL modem in the downstairs office, resulting in sluggish performance upstairs. Whatever version of WiFi we used would have worked better if the hardware had been planted higher up, in a more central part of the house.