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Mac to Mobile: Bluetooth & 802.11b Cleared Up


Yesterday’s reader mail on Bluetooth interfering with 802.11b opened up a can of worms and responses ranging from hostile to thoughtful. Obviously, many of us (yours truly included) are using Airport and Bluetooth simultaneously, especially with Ericsson T68 phones in the hands of both PowerPage readers and staff, so it’s possible for these devices to coexist. But it seems there may still be a possibility for interference between the two technologies, which occupy the same spectrum. And bean burrito lovers, take note: microwaves also emit raditiation in, you guessed it, the 2.4GHz spectrum.

According to the Ericsson Bluetooth FAQ “To avoid interference from other devices operating in the ISM band, Bluetooth wireless technology uses a technique known as frequency hop spread spectrum to make the link robust. The radio transceiver hops to a different frequency after each transmission and reception (1600 hops/ sec.).” Portable phones use the same technology, answering one reader’s observation that a couple of 2.4GHz phones can work together in the same room.

So everything’s fine, right? Not quite. Cross-modulation between devices can reduce throughput, as observed in our story about rumored Bluetooth-native PowerBooks. Proliferation of wireless devices poses bigger risks for the future, making it essential to improve performance in wireless-crowded conditions. One reader points us to a Toronto Star article that details this problem, albeit with a somewhat gloom-and-doom outlook. One possible solution advocated by the article: move Wi-Fi to a higher spectrum, as the new 802.11a protocol does. Call us crazy, but I think the safe bet is that Apple would be more than happy to have us all out buying new Airport hardware to do just that.

A note of policy: this website believes that democratic reader input from the highly-knowledgable Mac community ultimately provides deeper information about issues. As a result, we do occasionally publish reader mail that could be misleading or inaccurate, that does not represent the position of the staff. Many of the reader feedback published to yesterday’s story was likewise plain inaccurate, even as it accused of not checking facts. But please, keep the feedback coming: as you’ll see from yesterday’s feedback, ultimately this results in people who are true experts in a field responding. Thanks to all those who responded. We’ll make sure to deliver by researching these issues and posting follow-ups like this one to follow technological issues as they evolve and change.

By Jason O'Grady

Founded the PowerPage in 1995.