View Full Version : Atheros 2 minute delay problem - Best wireless cards
03-20-2008, 01:08 AM
I am an RF engineer who is new to this (802.11) environment but have quickly become aware of the Atheros problem with not recognizing that an AP has disappeared for 2 minutes. I am planning to use WirelessMon as a MetroMesh RSSI drive test tool and therefore have three primary requirements: the NIC must be PCMCIA compliant, have an external antenna port and be fairly quick and accurate with the RSSI readings. So far I have tested 6 different NICs (Intel Proset 2200, Ubiquity SRC, Proxim 8470-FC, Linksys WPC54G, Hawking USB, and Netgear USB WG111). The only two that work properly, that is have more or less instantaneous response to changes in RSSI are the Linksys and Netgear devices (Linksys (Broadcom chipset) best by far); unfortunately, neither comes with an external antenna. The Proxim and Ubiquity NICs do have an external antenna but come with the dreaded Atheros chipset and will hold an RSSI value for two minutes after the signal has vanished. Is there any solution to the Atheros problem? If not, are there any other NICs that someone could recommend that meet my requirements?
03-20-2008, 03:34 AM
We're not aware of any solution to the SSID caching problem, i had a look around for other Wireless card models that can be attached to external antennas but couldn't really come up with any suggestions for you to try (there was a cisco one but it isn't in production anymore).
Buffalo seem to have some USB models with upgraded antennas (http://www.buffalo-asia.com/cgi-bin/products/detail.cgi?country=ar&code=4&id=180 , http://www.buffalo-asia.com/cgi-bin/products/detail.cgi?country=ar&code=4&id=169 and http://www.buffalo-asia.com/cgi-bin/products/detail.cgi?country=ar&code=4&id=179) but if you're in the US it seems they have an ongoing court case and aren't supplying wireless equipment in the US and i'm not sure which chipset they are using.
03-20-2008, 02:39 PM
Okay then, I'm getting a Senao/Engenius card this am. It uses the Intersil Prism 2.5 chipset so I'm crossing my fingers. Thx. Love your app, btw.
03-20-2008, 10:49 PM
The Senao card didn't work worth a cr*p but I finally got my hands on an old Agere card (Lucent Orinoco 802.11b) that everyone swears by and sure enough, it works like a charm. Running WirelessMon at 0.1 second scan rate and it performs perfectly. Actually found two cards at my neighbor's house and they both perform identically. I have a free-standing 802.11b AP in the same small room and it makes a nice test transmitter. As far as I can tell, this card and the Linksys Broadcom card are the only two that truly respond to WirelessMon the way they need to in order to get accurate, mobile RSSI readings. Thx.
03-23-2008, 04:55 AM
The Proxim card runs into a problem when you are in a very congested area (lots and lots of APs) as in a business district with lots of WiFi around. WirelessMon gives a memory write error and has to be closed. I've played with the sampling period and sampling delay settings to no avail. Any thoughts? I don't have this problem with the Centrino or Linksys NICs. Thx
03-24-2008, 01:11 AM
Could you please run WirelessMon with the DEBUGMODE command line parameter (explained in more detail in the help file) and send us a copy of the log file that is created after you've reproduced the crash.
03-24-2008, 05:41 AM
Okay, I sent you an email. Thx
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