AirPort incompatibility with Atheros chipsets (commonly used in D-Link routers)

It appears that AirPort cards are incompatible with at least some chipsets manufactured by Atheros when said chipsets are used in repeater mode. The Atheros chipsets are commonly used in routers manufactured by D-Link including the DWL-2100 and other models.

MacFixIt reader Andew N writes "I have a wireless network setup with two D-link DWL-2100AP 802.11g units, one acting as an access point, one setup as a repeater to reach every corner of the building. The PC users are laughing at me as I can connect to the Access Point no problem, but the repeater appears to be invisible.

"I then tested the wireless network with a wireless PCMCIA card (D-Link DWL-G650) in the PC-card slot of my Powerbook, and used OrangeWare's great wireless PC-card driver.

"Guess what? The repeater was recognized and worked a treat."

"So my conclusion is that the Airport PC card is currently not compatible with the Atheros chipset (which D-Link uses)."

A poster on Apple's Discussion boards corroborated with a virtually identical issue. John Speer wrote "My neighbor uses a D-link DI-624 Wireless Access Point to interface with two PC's containing D-Link cards. I can interface with this wireless arrangement using my Powerbook with no problems. He recently added a D-Link DWL-2100 as a repeater (mode option). I can not link with the DWL-2100 in repeater mode at all with my Powerbook. The D-Link PC Cards, however, show the SWL-2100 signal presence. I can not understand why the Airport does not recognize the repeated signal. Possibly something associated with a BSSID code in the D-Link PC Card status information? I also would like the ability to connect to the D-Link repeater."

According to some further user posts on the bug tracking site binaervarianz.de, the incompatibility may stem from the fact that Atheros chipsets use the "short preamble" mode, and AirPort cards are not able to retrieve short preamble frames.

As such, it is advisable that users steer clear of D-Link 802.11g units as repeaters. Using D-Link wireless routers as base access points seems to pose no problem -- but in repeater mode, signals cannot be properly captured and used.

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